AWUS01 KWNH 191943
FFGMPD
LAZ000-ARZ000-TXZ000-OKZ000-200141-

Mesoscale Precipitation Discussion 0192
NWS Weather Prediction Center College Park MD
342 PM EDT Tue May 19 2026

Areas affected...north/northeast Texas, southwestern Arkansas,
northern Louisiana

Concerning...Heavy rainfall...Flash flooding possible

Valid 191941Z - 200141Z

Summary...A slow-moving complex of thunderstorms will continue to
produce local areas of 1-2 inch/hr rain rates. Isolated flash
flood issues are possible -- especially in low-lying and urban
areas -- through 0130Z/830p central.

Discussion...A mature, linear convective complex was making slow
southward movement across north/northeast Texas and the ArkLaTex
region over the past hour. The slow movement was occurring due to
weak steering flow aloft, slow propagation and expansion of a cold
pool upstream of convection, and continued, renewed updrafts along
the leading edge of the gust front. The airmass downstream of the
complex was strongly unstable (2000-2500 J/kg MLCAPE) and weakly
inhibited (negligible cap). These factors, along with the
presence of a weak mid-level wave over east Texas, should continue
to support scattered convection along and ahead of the complex for
the next several hours.

Slow movement and propagation has led to areas of 1-1.5 inch/hr
rain rates at times, with isolated 2 inch/hr spots near the most
persistent convection. This is generally lower that FFG
thresholds areawide, suggesting that any flash flood threat should
be tied to sensitive/urban terrain and mostly isolated in nature.=20
Occasional cell mergers should result in brief local peaks in rain
rates - especially with continued heating and ascent from the
mid-level wave near the region. Convection should reach the I-20
corridor in northeast Texas/north Louisiana over the next 2-4
hours (2130-2330Z).

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6ZAPFXnApdZj3yMlqvhhFcxkPa9cb9xwebc8N5Na5H78oEIPaHL-l6yDCZshhF3Guwzh= gGVamI0QoX0NCvIdA6kdbqU$ for graphic product...

ATTN...WFO...FWD...HGX...JAN...LCH...LZK...OUN...SHV...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 35059191 33339167 32279193 31719240 30909412=20
30699712 32089801 33139811 33669680 33679670=20
34009564 34329428 34959291=20

=3D =3D =3D
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AWUS01 KWNH 192332
FFGMPD
TXZ000-200530-

Mesoscale Precipitation Discussion 0193
NWS Weather Prediction Center College Park MD
731 PM EDT Tue May 19 2026

Areas affected...portions of west and central Texas

Concerning...Heavy rainfall...Flash flooding likely

Valid 192330Z - 200530Z

Summary...Slow-moving thunderstorms continue to produce high rain
rates - locally exceeding 2 inches/hr at times. Flash flooding is
likely on at least a localized basis.

Discussion...In the last half hour, an east-west oriented band of
cellular convection has intensified rapidly along an axis from
near Big Lake, TX east to near Llano, with other scattered
convection northeast of that axis (west of Waco) and also just
north of the Big Bend area. These storms were focusing along a
very slow-moving cold front in that vicinity. Furthermore, very
strong mid-level lapse rates (exceeding 8C/km) and near 70F
dewpoints were contributing to 3000-4000 J/kg MLCAPE, further
supporting strong updrafts. Weak steering flow was evident (only
20 knots or so at 500mb), enabling convection to exhibit slow and
at times erratic storm motions. Moisture/instability profiles
were supporting local 2-2.5 inch/hr rain rates that were
approaching FFG.

Overall increasing convective trends are likely to continue amid a
subtle increase in low-level flow into the aforementioned front
through the evening hours. Slow/erratic storm motions are likely
to continue with this activity, though upscale growth into a
convective complex appears probable as cold pools mature and
merge. Models hint at additional convection emanating from
northern Mexican higher terrain that may also organize and merge
with pre-existing convection across the discussion area and pose a
flash flood risk. Areas of 2-3 inch/hr rain rates are likely to
continue on at least a localized basis, posing a flash flood
threat especially in sensitive locales. 5 inch totals are also
possible. This threat is likely to continue through 05Z/midnight
central time, and a gradual eastward and/or southeastward shift in
flash flood potential should materialize, though this evolution is
likely highly dependent on how quickly storms can grow upscale
during the evening. Locally significant impacts are possible in sensitive/flood-prone areas.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5BnUTs18pNt79v1mrxFp1RI9sJob9cGID-yuhkGXdQhZExVWaWBLtEObLxJzhPJ7HSxo= 0ybwYKM-wB9jz9wB3vZCJJQ$ for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32169913 32029761 31589676 31199632 30409619=20
29599647 28919807 28499958 28340015 29080082=20
29660173 29460284 29830317 30790276 31910120=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 192355
FFGMPD
OHZ000-KYZ000-INZ000-ILZ000-200353-

Mesoscale Precipitation Discussion 0194
NWS Weather Prediction Center College Park MD
754 PM EDT Tue May 19 2026

Areas affected...southern Indiana, southwestern Ohio, northern
Kentucky

Concerning...Heavy rainfall...Flash flooding possible

Valid 192353Z - 200353Z

Summary...Scattered thunderstorms were exhibiting localized
training, with rates increasing to about 1 inch/hr on a localized
basis. Isolated instances of flash flooding are possible.

Discussion...Scattered thunderstorms were migrating eastward at a
decent pace across the discussion area this afternoon (~30 knots).
Storms in Ohio were organized into forward-propagating bands,
though upstream areas over Indiana into southwestern Ohio were
exhibiting slightly more favorable orientation for local training.
The convective orientation was favoring areas 1 inch/hr rain
rates on an isolated/spotty basis across the region, which was
approaching rather low FFG thresholds across the region due to wet
soils from prior rainfall the past few days.

Current trends suggest that an isolated flash flood risk will
exist for at least another couple hours. 1500-2000 J/kg MLCAPE
values and 1.9 inch PW values should sustain thunderstorms with
efficient rainfall rates at times through sunset. Thereafter, the
combination of surface cooling, convective overturning, and an
approaching front from the west should lead in a downtick in
convective coverage and attendant flash flood potential. Peak
risk will exist from now through around 03Z/11p eastern or so.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7Xq3kNuwUw8o0r4ib0YG7-HzIp87oQ6zkIH3E170SVZlDdZOcThaeQRxDGk7Pch8VxLH= c9LukOjbCkNkimrj4qU6JoQ$ for graphic product...

ATTN...WFO...ILN...ILX...IND...LMK...PAH...

ATTN...RFC...TIR...NWC...

LAT...LON 40188453 40048307 39338280 38688362 38318491=20
38128631 38118760 38638758 39088725 39628635=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 200415
FFGMPD
MSZ000-LAZ000-200815-

Mesoscale Precipitation Discussion 0195
NWS Weather Prediction Center College Park MD
1214 AM EDT Wed May 20 2026

Areas affected...southwestern to central MS

Concerning...Heavy rainfall...Flash flooding possible

Valid 200413Z - 200815Z

Summary...Brief training of heavy rain may allow for localized
hourly rainfall of 2 to 3+ inches from southwestern to central MS
over the next 2-4 hours. Localized flash flooding may result,
especially if overlap occurs within urban centers along I-55 from
Jackson to McComb.

Discussion...04Z radar imagery and surface observations showed a
NNE to SSW oriented line of thunderstorms moving east from western
MS along an outflow boundary. The environment was quite moist and
unstable with PWs between 1.8 and 2.1 inches along with 500-1500
J/kg MLCAPE as seen in the 00Z JAN sounding and 03Z SPC
mesoanalysis. The outflow boundary is expected to continue to
slowly but steadily move east over the next couple of hours but
recent development out ahead of the outflow in southwestern MS
near the LA border may support localized higher hourly rainfall
values aided by short term training. Where training sets up, the
environment supports the potential for 2 to 3+ inches of rain in
an hour and totals near 4 inches. Given the fairly high flash
flood guidance, this threat should likely be more urban in nature
or within other poorly draining locations.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-QXuIH5NQ7qC8QriiroSiKSFLqL9MVHxJJMa0lcAkNUWJ9_F09jgH9rSzliX55m3S2oQ= MQrZB7FhEs7A6R-qY8RGglg$ for graphic product...

ATTN...WFO...JAN...LIX...

ATTN...RFC...ORN...NWC...

LAT...LON 33398994 33018939 31359022 30949071 31019132=20
31449136 32039098 32769069=20

=3D =3D =3D
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AWUS01 KWNH 200552
FFGMPD
TXZ000-201150-

Mesoscale Precipitation Discussion 0196
NWS Weather Prediction Center College Park MD
151 AM EDT Wed May 20 2026

Areas affected...south-central TX to middle TX coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 200550Z - 201150Z

SUMMARY...Over the next 3-6 hours, localized flash flooding will
be possible over south-central TX to the middle TX coast due to
high rainfall rates locally exceeding 2 to 3 in/hr at times and
isolated storm total rainfall over 5 inches possible.

DISCUSSION...0515Z radar imagery showed a roughly west-east
oriented line of thunderstorms stretching from Kinney County to
Brazoria County. These storms were located along a composite
outflow boundary, sinking south, with an inflection point over
Colorado County due to prior merging of two outflow boundaries. An
northern bookend vortex/MCV feature, currently over Burleson
County, has been associated with some of the highest rainfall
rates with this complex. It is with this feature where
MRMS-derived rates had been 2 to 3+ inches per hour for a few
hours and local Wunderground sites near I-35 reported closer to 4
inches in an hour between 00-02Z.

High rain rates tied to the east-southeastward tracking MCV
feature over Burleson County are expected to wane over time as it
becomes further displaced from the better instability to the
south. Going forward, the outflow boundary is forecast to continue
dropping south with time into moderately strong MLCAPE of
2000-4000 J/kg and PWs of 1.8 to 2.1 inches via 05Z SPC
mesoanalysis data. While the outflow's exact motion remains
uncertain, given the convective line's orientation is not a
straight line, links/bends and short-term training will be
possible as it advances generally southward. 850-300 mb and 0-6 km
mean layer winds are less than or equal to 15 kt which will be
supportive of slow cell motions at times just behind or perhaps
just ahead of the outflow should pre-"frontal" cells form within
the highly unstable environment. Localized flash flooding may
result, including over a stripe of higher soil moisture due to 2
to 4+ inches of rain which fell early Tuesday morning from Aransas
to Corpus Christi Bay and westward.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6NX8hoVVmHJU-AZsF_YmMKPPVpyjpk0FfS99gLoSzn9YcYOidzlE--Jokl8NxLX16CqJ= ZRKEOMx7aZ60_kwXpULy9ik$ for graphic product...

ATTN...WFO...BRO...CRP...EWX...HGX...

ATTN...RFC...FWR...NWC...

LAT...LON 30409616 30379581 29519542 29159485 28759501=20
28239599 27799670 27359740 27339875 27679991=20
28730064 28990033 29019972 29039796 29519692=20
30009652 30259646=20

=3D =3D =3D
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AWUS01 KWNH 210110
FFGMPD
TXZ000-210708-

Mesoscale Precipitation Discussion 0200
NWS Weather Prediction Center College Park MD
909 PM EDT Wed May 20 2026

Areas affected...portions of western through central Texas

Concerning...Heavy rainfall...Flash flooding likely

Valid 210108Z - 210708Z

Summary...Scattered thunderstorms are beginning to expand in
coverage south of San Angelo. These storms may ultimately form a
complex that spreads areas of 2 inch/hr rain rates across portions
of the Hill Country overnight. Flash flooding is expected on at
least an isolated basis.

Discussion...Scattered thunderstorms are expanding in coverage
along an axis from near Ozona to near Menard - or along and just
north of I-10. The storms are associated with 1) a bowing complex
that originated from higher terrain over the TransPecos and 2)
along a remnant boundary/front from prior convection yesterday.=20
Storms were generally migrating eastward, but embedded in an
environment with steep lapse rates (downstream of an EML over far
west Texas) and supported by ~1500 J/kg MLCAPE along and south of
the aforementioned boundary.

As storms mature in this environment, they'll likely become prone
to multiple mergers and limited training over time as modest
low-level flow increases and results in convergence along the
aforementioned boundary. This will likely aid in spreading 2
inch/hr rain rates eastward over portions of the Hill Country that
received 2-4 inches of rain last night. Flash flooding is likely
in at least a few areas. Flash flood concerns may increase
substantially if storms can persist eastward toward the general
vicinity of Llano and Round Rock/Austin Metro. Those areas are
likely sensitive from previous rainfall and impacts that occurred
overnight last night.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6RysrWNZrAtRfRsVAq51_PTE14ve3ls0mbMRp3Fqo1j90__HWnMKIdTrbMrG5tOUZhrX= kC8us5KBUbkve15dJQ8TJlo$ for graphic product...

ATTN...WFO...EWX...FWD...HGX...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32199832 31839692 30559672 29509806 29530081=20
29860259 30770177 31250156 31660110 31810011=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 210229
FFGMPD
TXZ000-210815-

Mesoscale Precipitation Discussion 0201
NWS Weather Prediction Center College Park MD
1028 PM EDT Wed May 20 2026

Areas affected...Lower Rio Grande Valley/Deep South Texas...

Concerning...Heavy rainfall...Flash flooding possible

Valid 210230Z - 210815Z

SUMMARY...Initial slow moving cluster capable of 2"+/hr rates
should pre-wet the upper-soils as main line/wave emerges out of
Mexico in the middle of the overnight period. Localized 2-4"
totals, isolated 5" may result in isolated to widely scattered
flash flooding.

DISCUSSION...A very moist, conditionally unstable environment
exists in the lower Rio Grande Valley with a solid pocket of 2500
J/kg of uncapped MLCAPE remaining, given mid-80s temps over low
70s Tds. CIRA LPW along with RAP analysis/short-term forecasts
show enhanced low level moisture moving up the river valley with
winds recently backing in response to the approaching upstream
shortwave over the Big Bend exiting to the northeast and favorable
upper-level divergence pattern starting to emerge from the Sierra
Madre in E Coahuila into N Nuevo Leon. As such, recent
directional convergence in this response has seen fairly vigorous
convective initiation across Starr county and points across the
river in Mexico. Low level inflow has a few hours of
southeasterly moist/unstable inflow to maintain the cluster.=20
Given 2" total PWats and weak (less than 20kts of flow), moisture
loading and updraft vigor should support 2"/hr rates with
localized uptick to 2.5" possible. Deep layer sheared flow with
easterly flow in the low levels and weak confluent 700-500
steering flow from south to north, should allow for tilted
updrafts but slow moving to allow for increased residency. Spots
of 2-3" are possible.=20=20

The greater concern, is this cluster will continue to expand but
slowly weaken as the upstream inflow reduces (note veering profile
recently at KBRO/KCRP), but upper-level forcing via DPVA and
divergence aloft from the increasingly diffluent upper level flow
(right entrance over the Edwards Plateau) to provide favorable
environment for convective clusters to advance/merger out of the
Mexican highlands into the RGV generally timed after 06-07z. As
such, an additional 2-3" totals should occur and with overlap,
broader area of 2-4" with isolated 5"+ totals are possible.=20=20

While the area is in drought and have naturally higher FFG values,
urban centers and intense rates would be the main driver for
possible incident or two of localize flash flooding through the
overnight period.=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-sh4wMMi0kORMHE6gk5OMyl1GOh6y0rZBNZeISXBo8akF9v-3Zb0_irRrQTyH4uoXs6x= UYYPHCE85x5faDYsXQoE0Uk$ for graphic product...

ATTN...WFO...BRO...CRP...

ATTN...RFC...FWR...NWC...

LAT...LON 27889940 27549859 27139807 26509780 26139780=20
25989807 26229873 26429914 26979946 27539960=20
27749979=20

=3D =3D =3D
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AWUS01 KWNH 211120
FFGMPD
TXZ000-211419-

Mesoscale Precipitation Discussion 0202
NWS Weather Prediction Center College Park MD
719 AM EDT Thu May 21 2026

Areas affected...portions of the middle Texas Coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 211119Z - 211419Z

Summary...Areas of slow-moving, banded thunderstorm activity may
produce local rain rates of 2-3.5 inches per hour this morning.=20
Flash flooding is possible if this activity occurs over sensitive
locales.

Discussion...A mature MCS is making slow, steady progress along
portions of the lower Texas Coast and south Texas - generally
extending from near Corpus Christi southward to Brownsville. Slow
movement (around 20 knots - locally slower) and abundant
moisture/instability downstream over adjacent Gulf waters was
aiding efficient precipitation rates (around 3 inches/hr) in the slowest-moving, northern end of the complex.

Meanwhile, a new band has developed downstream of this complex
near Port Lavaca. This band is oriented more parallel to steering
flow aloft and perpendicular to the approaching complex from the
west. 2+ inch/hr rain rates are already being estimated with this
activity.

Over the next 1-3 hours, the forward propagation of the mature MCS
and slow-movement of the downstream convective band will promote a
prolonged period of heavy rainfall especially along/near the
middle Texas Coast. FFG thresholds of 2.5 inch/hr should be
eclipsed with this activity, and local totals of 5+ inches cannot
be ruled out through 14Z/9a central this morning. Flash flooding
is possible - especially if these rainfall totals occur over any
sensitive or low-lying/flood prone areas.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-TaqzPOzCrKt7UDQr6CNoE1rVSLFPXlqvLdXrSAS3wLtOXHa6Fl8YR0MaGcLyWZLuy80= jtx0p06eTw8IJ5YN6m9vNkc$ for graphic product...

ATTN...WFO...CRP...HGX...

ATTN...RFC...FWR...NWC...

LAT...LON 29209606 29159493 28569474 28449491 28289597=20
27999679 27399667 27369726 27739758 28459782=20
28959718=20

=3D =3D =3D
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AWUS01 KWNH 211706
FFGMPD
TXZ000-212304-

Mesoscale Precipitation Discussion 0203
NWS Weather Prediction Center College Park MD
105 PM EDT Thu May 21 2026

Areas affected...portions of west Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 211704Z - 212304Z

Summary...Areas of flash flooding will remain possible within an
axis generally extending from near Midland to near San Angelo and
San Saba.

Discussion...Scattered convection continues to focus along a
subtle surface boundary in the general vicinity of Midland to San
Angelo to near San Saba. Heating south of this boundary has
enabled 1500-2000 J/kg MLCAPE to develop with minimal inhibition,
supporting continued convection. Additionally, cool easterly
low-level trajectories and continued rainfall along and north of
the boundary was likely acting as a reinforcing mechanism to
continue maintenance of the boundary and continued updrafts.=20
Modest storm motions and backbuilding was supporting occasional
areas of 1 inch/hr rain rates to materialize with the most
persistent activity. These rain rates were approaching FFG
thresholds (around 1.5 inch/hr) on a localized basis.

Rainfall was occurring on ground conditions that are likely
sensitive from prior rainfall over the region in the last 72 hours
or so. Isolated instances of flash flooding cannot be completely
ruled out in this regime. While the persistence of this
convection regime is uncertain (and likely modulated by the
persistence and movement of the low-level boundary spawning the
convection across the region), models are generally consistent in
maintaining thunderstorm activity through the afternoon amid
southwesterly flow aloft. It is also worth noting that slightly
lower FFGs (around 1 inch/hr) exists generally from San Angelo to
Junction (just south of ongoing activity), which may represent a
slightly higher flash flood threat if heavier rain rates
materialize there.

Cook=20

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!94vsFyB58N6FlZzS3GXISzDBy84vGqb5ZhF1S8tquMYOC8itHL1ft6nW4mxkhDzjjcA3= XEYMxHG7vD5Rrz7CUAOpJVc$ for graphic product...

ATTN...WFO...EWX...FWD...LUB...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 33150160 32850033 31789879 31049845 30359895=20
30119970 30330071 31260172 32020240 32490268=20
32830244=20

=3D =3D =3D
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AWUS01 KWNH 212017
FFGMPD
TXZ000-OKZ000-KSZ000-220215-

Mesoscale Precipitation Discussion 0205
NWS Weather Prediction Center College Park MD
416 PM EDT Thu May 21 2026

Areas affected...portions of Oklahoma and western north Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 212015Z - 220215Z

Summary...Slow-moving thunderstorms are producing isolated spots
of rainfall rates approaching 2-3 inches/hr at times. Flash
flooding is possible on an isolated basis through 02Z/9p central.

Discussion...A complicated surface pattern exists across much of
Oklahoma currently. Prior moderate to heavy rainfall has resulted
in an expansive cold pool anchored across central Oklahoma as of
20Z. On the southern and eastern peripheries of this cold pool,
surface heating and subtle confluence along differential heating
zones has led to scattered thunderstorm development. The
pre-convective airmass supporting heavy rainfall is characterized
by 500-1000 J/kg MLCAPE and 1.5+ inch PW values, while weak
mid/upper steering flow has caused slow and at times erratic cell
motions, further promoting heavy rainfall. As of 20Z, the
heaviest rainfall was located near from the Wichita Mountains of
southwest Oklahoma southward through western north Texas and also
near McAllister and Okmulgee. FFG thresholds vary widely across
the region, but are lowest from north-central Texas through
eastern Oklahoma (around 1.5.2 inch/hr) and near 2.5 inch/hr
elsewhere across the discussion area. These FFG thresholds were
being exceeded on an isolated basis.

Overall trends will continue for at least a few hours, with very
slow/erratic movement and perhaps isolated upscale growth at
times. It appears that convection across southwestern Oklahoma
and western north Texas may prompt enough overturning with time to
stabilize the low level airmass and lessen the flash flood risk,
though this process may take some time to play out. Convection
over eastern Oklahoma may have greater longevity with a broader
pool of instability across that part of the state east of the
aforementioned central Oklahoma cold pool. Flash flooding will be
possible through 02Z/9p central.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9eem0gqBZ1QQPXCa5QlbilGhP1dPvi8_YngFOhgFdyjk_j9M5f3K7H8Pgoem8aPNb755= -BW6RSihhls-cmsIBnMPoCg$ for graphic product...

ATTN...WFO...FWD...ICT...LUB...OUN...SHV...SJT...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 37109630 36959488 35519453 34049465 33359645=20
32549786 32679963 33770046 34320034 34929972=20
35189882 35149795 35349757 36069754 36799728=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 212141
FFGMPD
TXZ000-220338-

Mesoscale Precipitation Discussion 0206
NWS Weather Prediction Center College Park MD
539 PM EDT Thu May 21 2026

Areas affected...portions of western and central Texas

Concerning...Heavy rainfall...Flash flooding likely

Valid 212138Z - 220338Z

Summary...Thunderstorms continue to increase in coverage over
sensitive areas from prior rainfall and terrain. Eventually,
urban areas near Austin, San Antonio, and Waco may be impacted.=20
Flash flooding is likely.

Discussion...Over the past hour or so, thunderstorms have
increased in intensity and coverage primarily across the Texas
Hill Country. These storms are likely responding to a couple of
changes in the thermodynamic environment: 1) heating of a moist
airmass southeast of ongoing convection, 2) recharge of mid-level
lapse rates from the EML originating over the southern Rockies,
and 3) subtle shortwave troughs aloft forcing ascent and aiding in
deep convective development. Weak low-level shear profiles
suggest that cells will continue to grow upscale into short linear
segments, but lingering boundaries from prior convection across
the region will also allow for convective mergers to occur as
well. The end result of this pattern will be continued
development of areas of 1-2.5 inch/hr rain rates over sensitive
regions from prior rainfall/wet soils, terrain, and eventually
urban surface in the Austin/San Antonio/I-35 vicinity. Given
ongoing trends, a greater likelihood of flash flooding exists,
with locally significant impacts possible.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7N3Zlz5LwXvP2OWRSWQUuLF_b-5pSjapIbqCSdDzSWjCC9xgy7gjbjJT2egs9tm716TJ= m5IobS1V_2a7P3881PHwdoA$ for graphic product...

ATTN...WFO...EWX...FWD...HGX...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32449676 31559583 29859604 28969855 29340094=20
30300207 31280174 31420055 31749905 32319814=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 220546
FFGMPD
TNZ000-MSZ000-LAZ000-ARZ000-221100-

Mesoscale Precipitation Discussion 0207
NWS Weather Prediction Center College Park MD
145 AM EDT Fri May 22 2026

Areas affected...Lower Mississippi Valley...

Concerning...Heavy rainfall...Flash flooding possible

Valid 220545Z - 221100Z

SUMMARY...Slow, efficient warm cloud rainfall with
training/repeating profile suggest localized 2-4" totals, with a
secondary maximum near deep layer cyclone pivot and downshear axis
across S Arkansas into N Mississippi.

DISCUSSION...GOES-E WV suite depicts a well defined mid-level
shortwave vorticity center across NE TX sliding northeast within
the broader southeast edge of the larger scale broad upper-level
trough. This provides deep layer DPVA and broad scale ascent with
the entrance to the upper level jet streak over the mid-MS River
Valley into the Great Lakes. At the surface, a weak surface wave
in central LA remains a bit south of a stronger 850-700mb low
along the AR/LA border, with a confluent surface to boundary layer
LLJ/warm conveyor belt surging moisture north through the MS river
and then bending back westward to the mid-level cyclone in the
TROWAL. This provides broad moisture flux convergence through the
area of concern; concurrent with bringing higher theta-E air into
the ascent region. Narrow-skinny profiles with solid surface heat
remaining provide a wedge of 500-1000 J/kg of uncapped MLCAPE
generally to the surface boundary with MUCAPE extending downstream
along the eastern branch of the TROWAL with 750-1000 J/kg into NE
MS.

The solid moisture confluence/convergence has broken out slow
moving scattered convection through portions of E LA/SW MS; with
slow motions and deeply saturated low level warm cloud processes
providing tropical shower efficiency supporting 2 to occasionally
2.5"/hr localized totals. Deep south-southwest steering to the
northeast will be slightly deflected eastward given surface backed
wind flow but given density of convective ascent pattern remains
solid will increase potential for repeating to support up to
focused 4" totals over the next few hours. Secondary maximum will
exist where 850mb flow rapidly backs from south/southwest to more southeast/east north of the boundary in the deformation zone that
generally parallels the front (though distance reduces further
east into S MS...steepening the isentropic ascent boundary). FFG
values are a tad lower within the MS River Valley (with 1hr spots
of 1-2"/hr and 3hr values of 2-3") suggesting a localize flash
flooding incident or two remains possible.

Additionally, downshear of the 850-700mb low, strong dynamic
ascent of the moisture flux into the western branch of the TROWAL;
has resulted in broad moderate rainfall, though there is very
limited instability that had not been worked over earlier this
evening. Still the dynamic strength combined with the high
moisture flux convergence should allow for increased duration for
some localized spots of 2-3"; this still may not reach higher FFG
in the area and may be more beneficial than resulting in flooding;
but the duration/efficiency could still pose localized concerns
enough to be included in the MPD area of concern through the
overnight period. All in all,

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6l8mB3m1mE34re-D5fPCgZzWvEit8IqqEwkaaV17iTCTz5h3r-pYqvgVLYQ0kZfErjPx= QmZ6MJgCbbIoHH5p70ZPYv0$ for graphic product...

ATTN...WFO...JAN...LCH...LIX...LZK...MEG...SHV...

ATTN...RFC...ALR...ORN...TUA...NWC...

LAT...LON 35138857 34738816 33868836 31688996 30979054=20
30359136 30359208 30819238 32139206 32759223=20
32859272 33229319 33849303 34289215 34709105=20
35018966=20

=3D =3D =3D
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AWUS01 KWNH 220827
FFGMPD
FLZ000-ALZ000-MSZ000-221230-

Mesoscale Precipitation Discussion 0208
NWS Weather Prediction Center College Park MD
426 AM EDT Fri May 22 2026

Areas affected...Coastal Mississippi and Alabama...

Concerning...Heavy rainfall...Flash flooding possible

Valid 220830Z - 221230Z

SUMMARY...Effectively stationary/back-building Gulf streamers may
result in localized very high totals and rapid inundation flooding
remains possible through early morning.

DISCUSSION...08z surface analysis, RAP analysis and sea-surface
state from satellite, denote a core enhanced pocket of higher
theta-E near surface pool resulting in near surface Tds in the
upper 70s east of 90E from the coasts of MS/AL southward for a few
hundred miles, generally within a area of confluent surface to
850mb flow as return south-easterlies around the N FL ridging
turns northward to intersect the south to southwesterly veered
flow influenced from the approaching deeper layer trough across
the Plains. While the core of the warm conveyor belt appears to
be shifted to the west responding from the approaching
height-falls; the surface regime is coming together near the
frictional convergence zone of the near shore/beaches. The core
of the SBCAPE axis of 4000-4500 J/kg is nosed to the MS beaches as
well. As such, confluent Gulf streamers have lead to early
morning convection focused on Mobile Bay and lingering affects of
the pre-frontal trof convection that dominated the Pearl River
Region yesterday.=20

While shallow, the deep layer flow is favorably oriented to
maintain the frictional convergence to support back-building that
will help to repeat in this localized focused axes. Total PWats
of 2", mainly loaded below 850mb (as noted in CIRA LPW above) with
values around 1" should allow for deep warm-cloud rainfall
generation processes and rain rates of 2.5"/hr. Already spots
have seen greater than 2.5" and an additional hour or so will
quickly result in rapid inundation. Proximity to urban centers
along the beach and I-10 would be at greatest potential for these
localize rapid inundation flooding events.=20

Hi-Res CAMs suggest, a slight disruption to the surface flow to
veer and reduce convergence at the surface shifting back west, but
with time, the core of the Warm Conveyor Belt will also shift,
especially given the instability axis remains upstream. So
additional thunderstorm activity is probable and may maintain risk
for localized inundation flooding through dusk.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5jt0nmx25bssA4QeIByEpASVgzJN1n2i8u4j7b7aXmhq1PPgUp4GNKhfv772pqBiSVk0= PrXDR3J5Wa8uzv9PxXayAEE$ for graphic product...

ATTN...WFO...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 31928789 31768733 31438714 31058717 30628740=20
30248771 30158788 30168851 30228948 30918911=20
31268888 31818829=20

=3D =3D =3D
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AWUS01 KWNH 220929
FFGMPD
OKZ000-KSZ000-221400-

Mesoscale Precipitation Discussion 0209
NWS Weather Prediction Center College Park MD
528 AM EDT Fri May 22 2026

Areas affected...Eastern Oklahoma... Adj SE KS....

Concerning...Heavy rainfall...Flash flooding possible

Valid 220930Z - 221400Z

SUMMARY...Mid-level convergence in TROWAL resulting in very slow moving/stationary elevated cells with 1.5"/hr rates. Localized
totals of 2" already with additional 1-2" possible may continue in
localized flash flooding.

DISCUSSION...Interesting deep layer dynamics environment with
moisture entrapment and weak instability to result in a narrow
band of heavy rainfall across eastern Oklahoma. GOES-E WV suite
depicts an elongated vorticity/shortwave center over Texarkana
moving northeastward with solid broad entrance region divergence
across E OK and AR and through the Ozark Plateau. RAP analysis
and VWP shows the western branch of the TROWAL is snaking from the
main LLJ over the MS river Valley, ascending over the front
westward through central AR before reaching an 850-700 convergence
boundary veering more north to south to enter the jet streak
aloft. CIRA LPW shows the enhanced core along this path with
total PWat values of 1.75" at in SE OK reducing to 1.5" toward SE
KS. Modest mid-level lapse rates support 500-750 J/kg of MUCAPE
through the 800-600mb layer and given moisture flux convergence
maximized at the base of that layer, convection has been weak but
sufficient for modest rainfall rates up to 1.5"/hr.=20

The slow/reducing forward propagation/deep layer steering has
further enhanced localized flash flooding potential given
increased residency time. Combine this with an axis of reduced
FFG values across the area of concern (especially in Tulsa Metro
area but even as far south as Pittsburg county) being about
1.5-2"/hr and generally less than 2.5"/3hrs; localized exceedance
remains possible through the late overnight period.=20

Eventually, winds further slacken as the DPVA from the shortwave
lifts further northeast into central AR and helps to sever the
remaining TROWAL; winds veer further to the west and should result
in a more widely scattered ascent pattern before weakening into
the early morning hours. Spots of 2"+ have already fallen across
the Pittsburg to Nowata county line with more scattered isolated
cells further south. MRMS Flash responses of greater than 400-600
cfs/sqmi have been noted in a few spots, especially in the urban
center near Tulsa. With an additional 1-2" totals, spots of
2-3.5" are probable and localized flash flooding will continue to
be possible through 13-14z.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4mlU_8DMbMaEU2XsJSjLePocjxD_pRnGR6SO06SQWe3eQhtO3n8hm22wTUZigLMwWVit= nxLT3KZVXZutqUwPIER0ZAc$ for graphic product...

ATTN...WFO...ICT...OUN...TSA...

ATTN...RFC...TUA...NWC...

LAT...LON 37269558 37019512 36279519 35549510 35229492=20
34869488 34639496 34479544 34769607 35559637=20
36469634 36959606=20

=3D =3D =3D
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AWUS01 KWNH 221520
FFGMPD
FLZ000-ALZ000-MSZ000-222115-

Mesoscale Precipitation Discussion 0210
NWS Weather Prediction Center College Park MD
1118 AM EDT Fri May 22 2026

Areas affected...Southeast MS...Southwest to Central AL

Concerning...Heavy rainfall...Flash flooding likely

Valid 221518Z - 222115Z

SUMMARY...Locally backbuilding and training convection are
expected to pose an increasing flash flood threat through the
afternoon. Rainfall rates of 2 to 3 inches/hour are expected, with
localized totals of 4 to 6 inches possible by mid-afternoon.

DISCUSSION...The regional environment is becoming increasingly
favorable for high-efficiency rainfall production. A 30 to 35 kt
southwesterly low-level jet is providing robust moisture transport
and low-level convergence along a quasi-stationary surface trough
situated from southeast MS through west-central AL. Precipitable
water values are currently pooling between 1.75 and 2.0 inches,
which is generally near or above the 90th percentile of
climatology for late May.

The 12Z morning KBMX sounding and recent RAP analysis confirm a
tropical-like thermodynamic profile with a deep warm cloud layer
exceeding 12,000 ft. This environment will support efficient
warm-rain physical processes, allowing convective cores to sustain
potentially extreme rainfall rates even with moderate instability.

MLCAPE values of 1500 to 2500 J/kg are nosing up along and just
east of the surface trough axis, and will support not only the
high rates, but also a general expansion of convection over the
next few hours as shortwave energy arrives from the southwest.
This will generally involve southeast MS through portions of
central and southwest AL for the main threat area.

Kinematically, the environment is primed for convective training.
Corfidi propagation vectors are largely offsetting the mean
steering flow, suggesting that cell development will tend to favor
at some backbuilding along and just ahead of the low-level
convergence axis. Hourly rainfall rates of 2 to 3 inches are
expected within the most persistent cores.

The antecedent conditions are generally rather moist based off the
latest NASA SPoRT-LIS soil moisture analysis, and the latest USGS
streamflow data shows somewhat elevated baseflows from recent
precipitation. These antecedent conditions will lead to high
runoff efficiency and potential rapid responses in small creeks
and urban drainage systems.

The latest hires CAM guidance suggests some localized rainfall
totals reaching 4 to 6 inches by mid-afternoon, and this will
likely result in some ares of flash flooding which may be locally
enhanced over the more sensitive urban corridors.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9Yb6DLWS_OSuo2U9mN0tNWik0R_qkLixek2AhTT-J5G6Vs2mToBqlpN6Sv2heFvQPl_x= JLpGBnTgAfBzmnm2cofKwWw$ for graphic product...

ATTN...WFO...BMX...HUN...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 33978649 33148629 31888665 30638735 30208792=20
30188888 30668911 32488827 33488790 33968734=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 221840
FFGMPD
GAZ000-TNZ000-ALZ000-222300-

Mesoscale Precipitation Discussion 0211
NWS Weather Prediction Center College Park MD
239 PM EDT Fri May 22 2026

Areas affected...Portions of Northern AL and Middle TN

Concerning...Heavy rainfall...Flash flooding possible

Valid 221839Z - 222300Z

SUMMARY...Northward-moving convection will pose a localized flash
flood threat through the afternoon and early evening. Rainfall
rates of 1.0 to 1.5 inch/hour are expected, with localized totals
of 2 to 3 inches possible where training occurs.

DISCUSSION...Convection currently over central Alabama is expected
to continue lifting north-northeastward into an environment
characterized by PWAT values of 1.6 to 1.8 inches and moderate
instability with MLCAPE values of near 1500 J/kg. While the
overall thermodynamic environment is less efficient than areas to
the south, a 30 kt low-level jet will continue to provide
sufficient moisture transport to support locally heavy rain rates.

The primary concern is the potential for localized cell-training
or backbuilding along the nose of the low-level jet. While
individual cells will be somewhat progressive, Corfidi vectors
suggest a component of the flow may allow for repeated rounds of
heavy rain over the same basins. Recent model guidance, including
the REFS ensemble, indicates a 20 to 30 percent probability of
exceeding flash flood guidance in localized areas, with some 2 to
3 inch rainfall totals possible by early this evening.

Given that soils are fairly moist across at least portions of
northern AL and middle TN, the rainfall over the next few hours
should favor at least an isolated threat for flash flooding. This
will tend to be mainly an urban threat, but with some of the
elevated terrain across the region, there may be some locally
enhanced and channeled runoff potential for some of the small
stream basins where any cell-training occurs.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5YJ7loOgBZcnIQxZOAUAtqGMVNQChjqtRYJVgkUMaZ09tsj4WCWqxhw5pLeMgMvbxuid= XgFZ3QIlR8_RTBfGQq2AmO8$ for graphic product...

ATTN...WFO...BMX...FFC...HUN...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 35608577 35518554 35228545 34698560 34228584=20
34008621 33938653 34068678 34598678 35318646=20
35528615=20

=3D =3D =3D
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AWUS01 KWNH 222024
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-230222-

Mesoscale Precipitation Discussion 0212
NWS Weather Prediction Center College Park MD
423 PM EDT Fri May 22 2026

Areas affected...southeastern Louisiana, southeastern Mississippi,
southern Alabama, and the western Florida Panhandle

Concerning...Heavy rainfall...Flash flooding likely

Valid 222022Z - 230222Z

Summary...Areas of thunderstorms continue to expand in coverage
and intensity across the discussion area. Rain rates are likely
to cause flash flood issues on at least an isolated basis.

Discussion...Deep convection has intensified and expanded in
coverage over the past hour - especially across southeastern
Louisiana and southeastern Mississippi. The storms are in a very
unstable airmass (80s F surface temps/mid-70s F dewpoints
supporting 2500 J/kg MLCAPE). Meanwhile, broadly confluent,
southwesterly low-level flow and weak inhibition was supporting
updrafts. Convection was oriented parallel to southwesterly
steering flow aloft, supporting localized training. Areas of
1-1.5 inch/hr rain rates were noted per MRMS imagery recently.

The storms were migrating over areas of relatively low FFG from
prior rainfall (approx 2 inch/hr thresholds in spots across SE
LA/SE MS, locally lower in southern AL). As cells migrate over
these regions of abundantly moist soils (and urban population
centers like New Orleans and Mobile), some risk of flash flooding
will likely arise. Convection (and flash flood risk) is likely to
be diurnally driven and weaken some shortly after sunset. The
eastern extent of flash flood risk from SE LA/SE MS convection is
in question, with widespread convective overturning across
portions of south-central Alabama has lessened instability values
there, and convection may struggle to be maintained with
northeastern extent. Portions of the Mobile, AL area may recover
from prior convective overturning and experience a renewed
thunderstorm/flash flood threat, however.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-eBMlkL1UBVI8zSV158CTwx2SMG9yBw5ckwsdbROPe7b0c9EUz-UaY1if5TtjMkdbrXm= 8fyw8xODLGeIAl_jXSvu_g4$ for graphic product...

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 32158672 32108561 30678610 30118715 29688992=20
29369046 29679156 30029176 30619173 31339010=20
31908888=20

=3D =3D =3D
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AWUS01 KWNH 222249
FFGMPD
VAZ000-WVZ000-OHZ000-TNZ000-KYZ000-INZ000-230447-

Mesoscale Precipitation Discussion 0213
NWS Weather Prediction Center College Park MD
648 PM EDT Fri May 22 2026

Areas affected...portions of Kentucky into southern Ohio and
western West Virginia

Concerning...Heavy rainfall...Flash flooding likely

Valid 222247Z - 230447Z

Summary...Scattered convection with embedded heavier rainfall will
continue to spread northward toward the middle/upper Ohio Valley
this evening. Moist ground conditions from antecedent rainfall
will raise the flash flood risk in a few areas.

Discussion...Scattered, deep convection continues along a general
axis extending from near Hopkinsville east-northeastward to near
Covington. These cells also happened to be collocated with a weak
warm front through that same aforementioned axis. Along and south
of the boundary, 70s F dewpoints were maintaining 1000-1500 J/kg
SBCAPE, fueling heavier convective elements and spots of 1 inch/hr
rain rates. A broad, negative-tilt mid-level trough over the
Mid-Mississippi Valley and stout low-level flow across
Kentucky/Tennessee was also providing ascent to support ongoing
convection.

This overall regime will gradually translate east-northeastward
over the next 3-6 hours. Areas of heavier rain will fall on
moistening soils that are gradually becoming more sensitive by the
hour due to abundant rainfall. FFG thresholds are around 1
inch/hr in most of Kentucky, but fall to around 0.5 inch/hr in
northeastern Kentucky into southern Ohio and western West
Virginia. As embedded convective elements reach these
water-logged areas, flash flood potential will increase. This
threat will exist through at least 02Z, with little indication
that rainfall rates will decrease after sunset.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!79d-Wj68ojWqCrsF2yZFQ9Wp4LOVbIFTpCrrFnY29cx7R9rwOHsyfzU0_zbHVPQjFPfS= RSRRU7RfQF_QvnaOf2138HI$ for graphic product...

ATTN...WFO...ILN...IND...JKL...LMK...MRX...OHX...PAH...PBZ...
RLX...

ATTN...RFC...ORN...TIR...NWC...

LAT...LON 40148277 39948082 38988042 38008173 37148259=20
36508336 36738469 36748661 36658801 37538804=20
38218691 39378497=20

=3D =3D =3D
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AWUS01 KWNH 230055
FFGMPD
MSZ000-LAZ000-ARZ000-TXZ000-230453-

Mesoscale Precipitation Discussion 0214
NWS Weather Prediction Center College Park MD
854 PM EDT Fri May 22 2026

Areas affected...northern Louisiana into central Mississippi and
far northeast Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 230053Z - 230453Z

Summary...Scattered thunderstorms were developing along a
confluence zone over the Mississippi Delta and adjacent northern
Louisiana. 1-2 inch/hr rain rates were estimated. These rates
will pose a flash flood risk for a few hours this evening.

Discussion...Persistent convergence along a confluence zone
extending from near Shreveport to near Monroe to near Rolling Fork
in southern portions of the Mississippi Delta. This confluence
zone was oriented parallel to west-southwesterly flow aloft,
supporting local cell training. In addition, abundant surface
heating along and south of this zone has enabled MLCAPE values to
exceed 2000 J/kg amid ~1.75 inch PW values. These thermodynamic
fields were enabling rain rates to reach 1-2.5 inch/hr in a few
spots. The highest rain rates were threatening FFG thresholds,
which generally range from around 1 inch/hr in MS to 2.5 inch/hr
in northern Louisiana.=20

Current trends suggest that most of the ongoing flash flood
potential will be diurnally driven, with a possible weakening
trend beginning after a few hours with loss of
heating/destabilization. Flash flooding will still remain
possible through at least 04Z/11p central given the favorable
thermodynamic environment supporting deep convection with
efficient rain rates. Flash flooding is possible - with
particular concern in low-lying spots and across central
Mississippi where ground conditions remain moist from prior
rainfall.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-bQo8_XKZHJ9aXvQz09CnEA9cf51h-P3yWBCIEcftfiA4QbNEtbDUbqQEfOtu9-YFbBi= 3WG0LA_iirluOe5cz512ON0$ for graphic product...

ATTN...WFO...JAN...LZK...MEG...SHV...

ATTN...RFC...ALR...FWR...ORN...NWC...

LAT...LON 34179016 33888932 32858903 32028984 31669202=20
31709464 32689489 33109381 33279199 33919108=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 231336
FFGMPD
MSZ000-LAZ000-TXZ000-231935-

Mesoscale Precipitation Discussion 0215
NWS Weather Prediction Center College Park MD
935 AM EDT Sat May 23 2026

Areas affected...Far Eastern TX...Central and Southern LA...Far
Southwest MS

Concerning...Heavy rainfall...Flash flooding likely

Valid 231335Z - 231935Z

SUMMARY...Expanding areas of heavy showers and thunderstorms, with
some localized cell-training will result in an increasing flash
flood threat through the mid-afternoon hours. Rainfall rates of 2
to 3 inches/hour are expected, with localized totals of 3 to 5
inches possible.

DISCUSSION...GOES-E satellite imagery and radar shows some small
scale MCS activity over far eastern TX along with an embedded MCV
that will be moving east into areas of western LA over the next
few hours. The latest surface data suggests a surface
trough/outflow boundary near the southern LA coast that extends
west-southwest back toward the Upper TX coast.

Meanwhile, the airmass is moderately buoyant with a nose of MLCAPE
values reaching 1500 to 2000+ J/kg across far eastern TX and
across much of western LA in association with modest, but
persistent southerly flow off the Gulf ahead of the upstream
convection. Moisture is heavily entrenched through the column
based off the latest OSPO ALPW data, with PWs overall running up
to near 1.75 inches.

The approaching convection and associated MCV energy is expected
to interact with this surface trough near the Gulf Coast, and
favor a general increase in warm air advection/isentropic ascent
that coupled with the nose of instability should favor an increase
in the coverage of heavy showers and thunderstorms. The latest
Corfidi vector analysis suggests at least some low-end threat for
backbuilding and training convection over the next several hours
as the convection increases across areas of central and southern
LA, and perhaps areas as far northeast as southwest MS.

High rainfall rates are expected that could reach 2 to 3
inches/hour with the stronger convective cores, and with any
cell-training, some localized storm totals going through early to
mid-afternoon could reach 3 to 5 inches. FFG is rather high across
the region overall, with moderate soil moisture (50 to 70 percent)
in the 0-10cm layer according to NASA SPoRT. However, with the
high rainfall rates and localized storm total potential, some
areas of flash flooding will tend to become likely over the next
several hours. This will especially be the case for the more
sensitive urban corridors.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-KQi3ZJNBFp2ejl5zDgZ2Jg7lR7tsfOr4FlcsN_tTCGKaKRIQE-FwBdhxhX2E3MwlWqg= Q56Fw7SOnkxhKJuE7DStGmM$ for graphic product...

ATTN...WFO...JAN...LCH...LIX...SHV...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON 31979285 31679154 31059027 30288969 29688969=20
29369007 29269094 29589253 29629308 29789379=20
30719441 31249432 31819377=20

=3D =3D =3D
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AWUS01 KWNH 231532
FFGMPD
TXZ000-232130-

Mesoscale Precipitation Discussion 0216
NWS Weather Prediction Center College Park MD
1130 AM EDT Sat May 23 2026

Areas affected...South-Central to Southeast TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 231530Z - 232130Z

SUMMARY...Expanding clusters of heavy showers and thunderstorms
will result in a regional threat for scattered areas of mainly
urban flash flooding going into the afternoon hours. Rainfall
rates as high as 2.5 inches/hour are likely, with localized totals
of 3 to 5 inches possible.

DISCUSSION...An ejecting shortwave trough/MCV crossing the Lower
Rio Grande Valley will be interacting with a moist and strongly
unstable airmass pooled along a surface trough currently situated
across areas of south-central to southeast TX and extending
offshore across the western Gulf. The approaching energy is
already driving multiple clusters of heavy showers and
thunderstorms across south-central TX, with a generally
progressive character off to the east.

MLCAPE values across south-central TX are on the order of 2500 to
3500 J/kg with PWs locally up around 1.75 inches. This coupled
with the forcing associated with the approaching shortwave
dynamics will facilitate rainfall rates as high as 2.5 inches/hour
over the next several hours as convection becomes increasingly
concentrated in close proximity to the aforementioned trough axis.

A general increase in the coverage of convection is expected going
into the afternoon hours across coastal areas of south-central to
southeast TX, including multiple metropolitan areas such as
Victoria and Houston. There will be some occasional instances
where the convection may repeat or train over the same area which
would drive heavier rainfall totals. The 12Z HREF/REFS suites
suggest some localized 3 to 5 inch rainfall totals going through
mid-afternoon.

Given the overall antecedent environment and expectations of
rainfall over the next few hours, there will be a threat for
scattered areas of mainly urban flash flooding.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!67tA2NnIsFCry5e7BmZ0XHM7XyUu3NYCaXM_7jr8-HPEQZiDiJ_vTrTxJBhO6VV1jkKR= 7nL6goKHbEJ3aW-k7ebGSFM$ for graphic product...

ATTN...WFO...BRO...CRP...EWX...HGX...LCH...

ATTN...RFC...FWR...NWC...

LAT...LON 30549440 29729390 28989499 28009653 27239714=20
26939766 27219814 27969832 28829814 29599742=20
30159643 30459547=20

=3D =3D =3D
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AWUS01 KWNH 231701
FFGMPD
WVZ000-OHZ000-TNZ000-KYZ000-232300-

Mesoscale Precipitation Discussion 0217
NWS Weather Prediction Center College Park MD
100 PM EDT Sat May 23 2026

Areas affected...Portions of the OH Valley

Concerning...Heavy rainfall...Flash flooding possible

Valid 231700Z - 232300Z

SUMMARY...Wet antecedent conditions and additional showers and
thunderstorms this afternoon may produce a localized threat of
flash flooding this afternoon.

DISCUSSION...The latest GOES-E satellite imagery along with
surface data shows an area of low pressure associated with an
upper trough across northwest OH. A trailing cold extends well to
the southwest of this with a warm front that is situated over
northern OH and down the west side of the Appalachians. A moist
and confluent low-level southwest flow pattern ahead of the cold
front is nosing up across much of central and eastern KY through
far western WV and eastern OH.

Warm sector MUCAPE values of 500 to 1000 J/kg and PWs of 1.5 to
1.75 inches are already in place generally from southern OH
through eastern KY, and this instability axis will lift a bit
farther north this afternoon as southwest flow ahead of the front
persists. Additionally, the latest visible satellite images show a
fair amount of solar insolation taking place across these areas,
and this is expected to yield a destabilizing boundary layer that
will couple with modest low-level forcing/convergence for
scattered bands of showers and thunderstorms over the next several
hours.

The mean layer flow is strongly unidirectional as seen on the 12Z
upper-air RAOB from KILN, and this will suggest a concern for some
localized training of these bands of convection. Already there is
one linear band of convection extending from southern OH into
north-central KY that has had a history of producing 1 to 2
inch/hour rainfall rates, and these high rates should be
sustainable this afternoon with the addition of more surface heating/instability.

The latest hires CAMS may be slightly underdone with the
convective threat and the overall QPF footprint this afternoon
considering the training potential. Given the rates and training considerations, some localized 2 to 3 inch rainfall totals will be
possible. The antecedent conditions are rather wet, and this
coupled with the additional rainfall potential may support some
localized areas of flash flooding this afternoon.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!71-1H9gosDQS7QWA22Ig2vHwXXspPL-ipWp4cf75PDtajGxyot6U94zt82aqcLLd8RXr= wkBrTuw9zAOXHJHtejK6zkI$ for graphic product...

ATTN...WFO...CLE...ILN...JKL...LMK...MRX...OHX...PBZ...RLX...

ATTN...RFC...TIR...NWC...

LAT...LON 41218183 41148115 40618058 39278102 38118192=20
37028306 36428420 36508513 36968551 37598527=20
38248439 38978374 39828308 40888251=20

=3D =3D =3D
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AWUS01 KWNH 231753
FFGMPD
ALZ000-MSZ000-LAZ000-ARZ000-232345-

Mesoscale Precipitation Discussion 0218
NWS Weather Prediction Center College Park MD
152 PM EDT Sat May 23 2026

Areas affected...Southeast AR...Central and Southern
MS...West-Central AL

Concerning...Heavy rainfall...Flash flooding possible

Valid 231752Z - 232345Z

SUMMARY...Isolated to scattered areas of flash flooding will be
possible this afternoon and early this evening from showers and
thunderstorms with high rainfall rates capable of reaching 2 to 3
inches/hour.

DISCUSSION...The latest GOES-E IR/WV suite shows a cold-topped MCS
and embedded MCV continuing to advance east across central LA with
recent radar trends showing downstream convective development
across areas of southeast AR through central and southern MS. This
energy will be interacting over the next several hours with a
strongly unstable and moist environment characterized by MLCAPE
values of 2000 to 3000+ J/kg and PWs over 1.75 inches.

There is evidence of a surface trough across south-central MS
which recently seems to be facilitating some of the development
and expansion of convection across this region. The latest HRRR
and RRFS guidance suggests rainfall coverage increasing over the
next few hours as the upstream energy with the MCV approaches, and
there is likely to be areas of relatively concentrated convection
by later this afternoon that will be capable of producing very
high rainfall rates. Given the thermodynamic environment, there
will be some rainfall rates likely reaching 2 to 3 inches/hour.

The high rates and relatively concentrated nature of the
convection may support some rainfall totals that reach 3 to 4+
inches by early this evening. Recent rainfall across portions of
the region have allowed for the antecedent environment to become
more sensitive, with increasing soil moisture concentrations. As
such, the additional rainfall this afternoon may favor a concern
for isolated to scattered areas of flash flooding. This would also
include concerns for some of the more sensitive urban areas.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-xFujvhWvvLzNFZ1UlbBP_b4zFp39b1trxk9DdKvh_l8QF6cBvQ4UvK2w3qdnzoWc3NP= WYce8OlhfKTX9TbjcWsXkmo$ for graphic product...

ATTN...WFO...BMX...JAN...LZK...MOB...SHV...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34119119 33279025 33098908 32808816 32478781=20
31938776 31568825 31398904 31459029 31749128=20
32279185 32659211 33599235 34109210=20

=3D =3D =3D
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AWUS01 KWNH 231852
FFGMPD
SCZ000-GAZ000-232345-

Mesoscale Precipitation Discussion 0219
NWS Weather Prediction Center College Park MD
252 PM EDT Sat May 23 2026

Areas affected...Northeast Georgia through North-Central South
Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 231849Z - 232345Z

SUMMARY...Heavy thunderstorms, with some localized cell-training
bring an increasing flash flood threat rest of the afternoon from
northeastern Georgia through north-central South Carolina.
Rainfall rates of 1 to 2 inches/hour are expected, with localized
totals of 3 inches possible over already saturated ground.

DISCUSSION...Moist/unstable air flowing into the cold air damming
wedge front over northeastern Georgia. This front is providing a
focus for thunderstorm development generally west from Augusta.
Southerly low level flow with effective shear of 25 to 30kt is
allowing redevelopment along/beyond this front with SBCAPE of 2500
J/kg and PW of 1.9" allowing hourly rainfall of 1.5 inches/hour in
spots. The cold wedge front has been receding north which brings
the focus into the area that saw 2-5" rainfall last evening. FFG
of 1 to 1.5 inches/hour is along the current frontal location from
GA to the flash flood sensitive Columbia, SC.

Continued heavy rain over this already saturated area should cause
localized flash flooding into this evening. Instability decreases
rapidly north of the front keeping areas such as Greenville, SC
away from the heavy rain at least for the next several hours.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9RyitIh4Q531mORIBqfHAg4s-K5xQ0fAwBaQdryk86pCizdxhuOqrhyPtZa-Sj2OpHoi= mAnZCOHKxG2jkKUwsj1MzO8$ for graphic product...

ATTN...WFO...CAE...FFC...GSP...

ATTN...RFC...ALR...NWC...

LAT...LON 34828348 34748305 34658266 34478215 34578138=20
34508044 33988084 33758132 33478194 33418220=20
33448252 33608292 33918330 34488351=20

=3D =3D =3D
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AWUS01 KWNH 232032
FFGMPD
MOZ000-ARZ000-OKZ000-KSZ000-240130-

Mesoscale Precipitation Discussion 0220
NWS Weather Prediction Center College Park MD
431 PM EDT Sat May 23 2026

Areas affected...Southwest Missouri into Kansas and Arkansas

Concerning...Heavy rainfall...Flash flooding possible

Valid 232030Z - 240130Z

SUMMARY...Heavy thunderstorms repeating near a frontal boundary,
bring an increasing flash flood threat into this evening over
southwest Missouri into Kansas and Arkansas. Rainfall rates up to
2 inches/hour are expected, with localized totals of 3 inches.

DISCUSSION...An MCV over northeast OK is riding along a stalling
frontal boundary over far southeast KS into central MO. The warm
sector activity extends from northwest AR up to west-central MO.
Sufficient moisture with PW of 1.5" and instability with SBCAPE of
1500 J/kg will continue to allow heavy thunderstorm development
rest of the afternoon. Light shear over the area causes slow storm
motion while southerly low level flow recharges the environment
through the frontal convergence. FFG is generally around 1.5
inches/hour which has been observed the past hour over southwest
MO. SWly jet level flow will continue to push the MCV along the
front and maintain heavy rain ahead of it into the evening.

Recent HRRR and RRFS runs do not handle the MCV well and result in
too dispersive QPF into the evening. Given radar trends and the
moist/unstable environment, localized flash flooding can be
expected into the evening hours in areas with lower FFG, urbanized
areas, and in the highest precip totals. The activity should
eventually progress east, so further discussions may be warranted
into the overnight hours.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-TfOJddi27ltmW5likwsam9bAO2tNIfqIk9VWDQNuV_g7ndjfLDdWo1yvtj6xwMHSTaU= oOSfMd3JLA0U0O0XA3Kqats$ for graphic product...

ATTN...WFO...EAX...ICT...LSX...LZK...SGF...TSA...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON 39009285 38669251 36609311 36119357 36589439=20
37069474 37219544 37469539 37829483 38579382=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 240018
FFGMPD
PAZ000-WVZ000-OHZ000-KYZ000-240530-

Mesoscale Precipitation Discussion 0221
NWS Weather Prediction Center College Park MD
817 PM EDT Sat May 23 2026

Areas affected...Upper Ohio Valley

Concerning...Heavy rainfall...Flash flooding possible

Valid 240016Z - 240530Z

SUMMARY...Saturated soils and additional prefrontal thunderstorms
this evening should continue to produced localized flash flooding
over the Upper Ohio Valley into the overnight.

DISCUSSION...A plume of moisture extends north up the west side of
the Appalachians and the Upper Ohio Valley west of the cold air
damming west on the east side of the Appalachians and ahead of a
cold front over northern Ohio. A moist and confluent southwesterly
low-level flow through this plume is providing 1.6" PW which is 2
standard deviations above normal over southeast OH, western WV,
into far western PA.

Warm sector MLCAPE values of 1000 J/kg and the abundant moisture
will continue to support scattered bands of heavy thunderstorms
through the evening. Deep layer unidirectional SWly flow persists
over this region which should maintain localized training of these
bands of convection. Hourly rainfall up to 1.5 to 2" is likely to
continue in training activity which is in agreement with recent
HRRR/RRFS runs. The antecedent conditions are rather wet with
flash flood guidance generally 1" or less. Therefore localized
flash flooding can be expected into the overnight. Late night
nocturnal trends may preclude the need for further discussion in
this area overnight, though that will continue to be monitored.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_qTo1ziUydoIoJLKNj985gDznN4aCtucEOni6CUIa39iu4qt7sOyXV8xjsIpWMs9OhT7= z1bgPrqXS64u2i5xlZniOj4$ for graphic product...

ATTN...WFO...ILN...JKL...LMK...PBZ...RLX...

ATTN...RFC...TIR...NWC...

LAT...LON 40638122 40428064 39978035 38938106 38068215=20
37668342 38328420 39048362 39898219=20

=3D =3D =3D
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AWUS01 KWNH 240125
FFGMPD
MOZ000-ARZ000-240630-

Mesoscale Precipitation Discussion 0222
NWS Weather Prediction Center College Park MD
924 PM EDT Sat May 23 2026

Areas affected...Ozarks

Concerning...Heavy rainfall...Flash flooding possible

Valid 240123Z - 240630Z

SUMMARY...Heavy prefrontal thunderstorms repeating into the
overnight maintain a localized flash flood threat over southern
and northern Arkansas. Rainfall rates up to 2 inches/hour are
expected, with localized totals of 3 inches.

DISCUSSION...Outflow from earlier activity is maintaining
convergence from southerly flow and renewed growth over northwest
AR into southeastern MO. Sufficient moisture with PW of 1.5" and
instability with MUCAPE of 1000 J/kg will continue to allow heavy
thunderstorm development into the overnight. Light shear over the
area causes slow storm motion while southerly low level flow
recharges the environment through the frontal convergence. FFG is
generally higher, around 2.5 inches/hour despite this being the
flood prone Ozarks.

Recent HRRR runs have a decent handly on this ongoing activity
while the RRFS is underdoing it. Given radar trends and the
moist/unstable environment, localized flash flooding can be
expected into or through the overnight hours where highest precip
totals occur.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9gQcWATB0duFocmJ93-PRp-o5AafAvFLlEM13Zxlu3UW1dJ5hY5uYQkM3N6x6okcHSFZ= B1Y7DqnmBssIveydCnLEjmU$ for graphic product...

ATTN...WFO...LSX...LZK...MEG...PAH...SGF...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 37989132 37569065 36309042 35409209 35339412=20
35899423 36369341 36859254 37359213 37909200=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 240651
FFGMPD
ALZ000-MSZ000-LAZ000-241200-

Mesoscale Precipitation Discussion 0223
NWS Weather Prediction Center College Park MD
250 AM EDT Sun May 24 2026

Areas affected...Southeast LA...Coastal MS & AL...

Concerning...Heavy rainfall...Flash flooding possible

Valid 240650Z - 241200Z

SUMMARY...Strong MCV with WAA training profiles increasing
residency and therefore overall totals to allow for rapid
inundation flooding.

DISCUSSION...KHDC shows a very mature MCV with a tight inner
convective core as well as a leading forward propagating leading
band moving through the mouth of the Mississippi River and through
the Chandeluer Islands. The strong outflow and localized pressure
falls continues to support rapidly backed low-level inflow over
the area of the north central Gulf that has remained over 80
degrees and therefore increasing downstream theta-E advection and
moisture flux.=20

The latent heat release and favorable outflow orientation to a
great outflow channel into the right entrance of the 80-90kt speed
max continues to maintain and actually recently strengthen the
MCC/MCV. RAP analysis and local observations show the downshear
WAA off the Central Gulf has increased deep layer moisture to near
2"/hr but also has pulled the instability gradient across the
Chandeleur to central MS Coast and into south-central AL with
MLCAPEs over 1500 J/kg along and downstream. This all has
sharpened the effective warm front/deformation zone increasing low
level isentropic ascent/moisture convergence along and ahead of
the dense central core. Rates of 2-2.5"/hr are likely given the
strength of the flux convergence and upward vigor of updrafts over
the next few hours. As the convection continues to expand along
the warm front, training/repeating will increase to support
increased residency for localized 2-4" totals, with and isolated
5" total possible in the 2-3 hours as it the band/core passes.=20

The limiting factors will be placement relative to the land, with
the core likely to remain SE of NOLA proper, but given deep layer
steering look to come along the MS coastal area into S Alabama,
where recent very high rainfall totals over the last 2 days or so
have saturated the upper soils. FFG values have recovered, but
given 0-40cm soil ratios, across portions of the MPD and overall
rates of warm cloud tropical rainfall could result in rapid
inundation flooding through the late overnight period and early
morning.=20=20

There is some uncertainty for trailing redevelopment South of SE
LA, where confluent rear-inflow streamers could reform. About
half of Hi-Res CAM suite suggests this redevelopment may persist,
though environment may take too long to recover to have higher
confidence, but the risk does remain.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5WIMBt4M39pYQ2L9f9XMTzG-N_06pU65Cs6ECrcP_0u-YolHoT7wpFM9glweOGgrCsbs= -yb5i67558CstYHz17P4vkk$ for graphic product...

ATTN...WFO...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 31998811 31638766 31038759 30148821 29078933=20
29079008 29639038 30648984 31288947 31908895=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 241709
FFGMPD
PAZ000-VAZ000-WVZ000-OHZ000-TNZ000-KYZ000-INZ000-242305-

Mesoscale Precipitation Discussion 0225
NWS Weather Prediction Center College Park MD
108 PM EDT Sun May 24 2026

Areas affected...Central and Eastern Kentucky...Southern and
Eastern Ohio...Central and Western West Virginia

Concerning...Heavy rainfall...Flash flooding likely

Valid 241708Z - 242305Z

SUMMARY...Convective coverage and intensity will gradually
increase and expand eastward through late this afternoon ahead of
an approaching MCV. Hourly rainfall rates of 1.0 to 1.5+ inches
overlapping with highly sensitive soils will make scattered areas
of flash flooding likely.

DISCUSSION...Regional radar and visible satellite imagery early
this afternoon depict an expanding area of efficient showers and
deepening convective clouds advancing downstream from an MCV
currently migrating out of western Kentucky. While morning
activity was generally subdued, continued diurnal heating is
actively destabilizing the boundary layer across a broader
footprint. This increasing instability is fostering an expansion
of convective coverage and updraft intensity that will track
eastward across central/eastern Kentucky, southern/eastern Ohio,
and into central/western West Virginia over the next several hours.

The 12Z high-resolution guidance suite (including the HREF and
REFS) shows neighborhood probabilities for 1 inch/hr rainfall
rates increasing toward 30-50% across the region, with a notable
uptick in signal pushing into central and western West Virginia by
late afternoon. Furthermore, the deep-layer mean steering
flow?oriented southwest to northeast?will parallel the initiating
boundaries, strongly favoring cell training. The latest CAM
consensus points toward localized rainfall totals of 2 to 4 inches.

The primary driver for the flash flood threat remains the low land
surface capacity across this entire region. Recent soil moisture
data and RFC Flash Flood Guidance indicate that the basins across
the Ohio Valley and into the Appalachian foothills of West
Virginia are already sensitive. The 12Z HREF/REFS blend shows a
robust and expanding 30-50% probability of exceeding these low
3-hour FFG thresholds. Given the antecedent conditions and
potential for training convection, any 1.0-1.5"+/hr rates will
drive runoff concerns, and likely overwhelming some small streams,
creeks, and low-lying infrastructure. Therefore, scattered areas
of flash flooding are generally likely this afternoon.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8wmf-1b4SO41LV9d8--fOutJehNOzV4EU5Du1lyJ4ba5kDdijOKgld-gB06nRVHlNRXt= 8hN6eftIqVYMWyIFKZC_w90$ for graphic product...

ATTN...WFO...CLE...ILN...JKL...LMK...MRX...OHX...PBZ...RLX...
RNK...

ATTN...RFC...ORN...TIR...NWC...

LAT...LON 41218178 41208087 40818047 40058038 39258035=20
38288059 37358159 36998231 36558393 36558497=20
36678542 37358529 37958574 38488562 39158465=20
39708363 40608255=20

=3D =3D =3D
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AWUS01 KWNH 241619
FFGMPD
GAZ000-TNZ000-ALZ000-242215-

Mesoscale Precipitation Discussion 0224
NWS Weather Prediction Center College Park MD
1217 PM EDT Sun May 24 2026

Areas affected...Central to Northeast Alabama...Northwest
Georgia...Middle Tennessee

Concerning...Heavy rainfall...Flash flooding likely

Valid 241617Z - 242215Z

SUMMARY...Convective coverage and intensity will continue to
expand early this afternoon as an MCV lifts northeastward.
Rainfall rates of 1-2+ inch/hr, with localized maximum totals of
2-4 inches, will make scattered areas of flash flooding likely
this afternoon given the moist antecedent conditions.

DISCUSSION...Regional radar and satellite imagery depict an
expanding area of convection across central and northern Alabama,
driven by a well-defined MCV and associated mid-level shortwave
lifting northeastward. A coupled pocket of 850mb convergence and
250mb divergence is providing robust synoptic lift. Concurrently,
diurnal heating has actively destabilized the boundary layer,
allowing MUCAPE values to surge into the 1000-2000 J/kg range.
Combined with PWATs pooling between 1.7 and 1.9 inches, the
environment is primed to support highly efficient convection with
high rainfall rates.

High-resolution guidance is in strong agreement regarding the
evolution and intensity of the afternoon convection. The 12Z HREF
highlights 50-70+ percent neighborhood probabilities for 1 inch/hr
rainfall rates across the region, with 20-30+ percent
probabilities for rates exceeding 2 inch/hr. The latest HRRR
guidance corroborates this intensity, suggesting localized total
accumulations of 2 to 4 inches through the afternoon as the
convective footprint expands from into northeast Alabama, middle
Tennessee, and eventually farther east with areas of northwest
Georgia seeing a threat.

The combination of high-end rainfall rates and expanding coverage
will pose a flash flood threat. The 12Z HREF shows 40-50 percent
probabilities for exceeding 3-hour Flash Flood Guidance (FFG)
across the targeted area. The intersection of 2+ in/hr rates with
the sloped terrain of the Cumberland Plateau and the more
sensitive urban corridors will lead to potentially more enhanced
runoff concerns, and thus overwhelming local drainage systems and
small streams. Overall, scattered areas of flash flooding are
likely across the region over the next several hours.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6nkighx3wfEaDfsRHYQ0MhHTbyp29_-ejb0xkuaYufEx4KbxZpsH8vZ_hA8tHPdKgJQC= NcV3s8kz7dqvcNxHQg_s_JI$ for graphic product...

ATTN...WFO...BMX...FFC...HUN...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36468476 35738436 34498476 33188559 32538648=20
32458709 32918767 33688768 34738719 35588649=20
36328568=20

=3D =3D =3D
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AWUS01 KWNH 242026
FFGMPD
FLZ000-GAZ000-ALZ000-250130-

Mesoscale Precipitation Discussion 0226
NWS Weather Prediction Center College Park MD
424 PM EDT Sun May 24 2026

Areas affected...Southern Georgia

Concerning...Heavy rainfall...Flash flooding possible

Valid 242024Z - 250130Z

SUMMARY...Repeating thunderstorms bring isolated flash flood
threat to southern/central Georgia into the evening. Rainfall
rates of 2-3 inch/hr will continue with localized maximum totals
of 3-5 inches for this area which is not flood prone.

DISCUSSION...Regional radar and satellite imagery depict an
east-west oriented line of scattered heavy thunderstorms
developing on low level convergence over southern Georgia with
further upstream development in far north Florida. Instability is
robust with SBCAPE of 3000 J/kg and moisture is extreme with 2.2
inch PW (2.5 sigma above normal) supporting highly efficient
convection with high rainfall rates of up to 3 inches/hr.

Recent hRRR and RRFS runs are on the lighter side for rainfall
compared to radar estimates. Fair rates of northward movement will
continue with SSWly deep layer mean flow generally around 20kt.
However, the additional upstream development and cell interactions
make a concern for localized maxima of a quick 3-5 inches of
rainfall in the coming few hours which would exceed the general
flash flood guidance near 3 inch/hr. This activity will continue
moving north and could bring concerns this evening to more
sensitive areas such as Atlanta and areas of northeast GA into SC
which have seen more rain in recent days due to the persistent
cool air damming.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!73FTkC8m3598p8gBqwfzYyI6uf2NojWFSmkB9fund5L1uUQr5HyXr55Be9nysJZEbyNF= f2-dFCqIYmHWYyMB6looUog$ for graphic product...

ATTN...WFO...BMX...FFC...JAX...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 33088432 32998344 32688250 31878236 31108254=20
30458283 30348394 30698518 31418572 31938558=20
32568537 32848500=20

=3D =3D =3D
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AWUS01 KWNH 242102
FFGMPD
TXZ000-OKZ000-250200-

Mesoscale Precipitation Discussion 0227
NWS Weather Prediction Center College Park MD
500 PM EDT Sun May 24 2026

Areas affected...Dallas-Forth Worth Metro

Concerning...Heavy rainfall...Flash flooding possible

Valid 242100Z - 250200Z

SUMMARY...Localized flash flooding over the greater Dallas-Fort
Worth metro into this evening from slow moving heavy thunderstorms
producing up to 4" rainfall.

DISCUSSION...As of 21Z...thunderstorm clusters north of Ft. Worth
and southeast of Dallas have developed in a moist/unstable
environment. Instability is typical for North Texas summertime
convection with SBCAPE around 3000 J/kg as is moisture with PW
around 1.5" and dew points in the upper 60s. Light flow will
continue to allow slow movement and popcorn type convection
developing off outflow boundaries. Rainfall rates up to 2"/hr
estimated by KFWS in the past hour should generally hold true for
subsequent convection through the evening. There is a risk for
some repeating convection/cell mergers which could allow localized
4" totals which would be a concern for flash flooding, especially
in the broad urbanized areas of the metro.

Recent HRRR runs are underestimating the ongoing activity and
generally underplay the heavy rainfall threat for this metro area
into this evening. Hail is a concern with this activity, but
enough rainfall should occur to cause localized flash flood
concerns into the evening. Further thunderstorm development to the
south may warrant additional discussions in Texas through this
evening.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8-WaSVXFsd4dfERNS-1ssz10PzDgVEXMLkl2Kf2TtZtIl6kWR1Sz5COVFouQlCK-FWk6= -RIq4BmaA1BeQgIfgvR3w9w$ for graphic product...

ATTN...WFO...FWD...OUN...SHV...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 33869791 33819644 33449506 32469498 31939579=20
32039707 32369854 33489887=20

=3D =3D =3D
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AWUS01 KWNH 242222
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-250330-

Mesoscale Precipitation Discussion 0228
NWS Weather Prediction Center College Park MD
621 PM EDT Sun May 24 2026

Areas affected...North Georgia into South Carolina and Southern
Appalachians

Concerning...Heavy rainfall...Flash flooding possible

Valid 242218Z - 250330Z

SUMMARY...Widespread convection with embedded high intensity
rainfall lift over Georgia and South Carolina this evening.
Additional convection over eastern Tennessee will also continue
ahead of an MCV lifting past Chattanooga. Rain rates of 2"/hr with
localized maximum totals of 2-4 inches will make scattered areas
of flash flooding likely through this evening given the moist
antecedent conditions.

DISCUSSION...As of 22Z...an MCV is moving over Chattanooga while
scattered heavy convection is over the Atlanta metro east into
South Carolina with an organized line of convection lifting from
southern Georgia. This area has upper support from increasing
right entrance jet dynamics over the eastern TN Valley and low
level support in the form of topographic lift in the southern
Appalachians as well as a remnant cool air damming wedge over the
upland area of SC into northeast GA. Ample instability is present
with 2500 J/kg SBCAPE over the GA/SC border and generally 1500
J/kg elsewhere. A pool of 2.2" PW air is lifting north from
southern GA while the 2" PW contour currently reaches Atlanta per
the 22Z RAP mesoanalysis. Ongoing activity in northern Atlanta
combined with the progress of southern GA activity warrants
including Atlanta in this discussion area. The environment in the
discussion area supports highly efficient convection with high
rainfall rates.

As is the recent trend, HRRR runs this afternoon are underdoing
current activity, while the RRFS has maxes that are too hot in GA,
but also too low in eastern TN per recent radar trends. Taking an
average of the two makes for a more reasonable solution with a
threat for 2-4" maxima through 03Z with 4-5" possible along the
GA/SC border area.

The combination of high-end rainfall rates and threat for
repeating activity in deep layer SSWly flow of 25kt poses a
scattered flash flood threat through the evening. The cool air
wedge has kept heavy rain from the southern Apps in recent days,
so the antecedent conditions are worse on the Piedmont/Cumberland
Plateau. There is a localized flash flood threat in the southern
Apps tonight as the wedge continues to break down and subtropical
moisture encounters orographic lift.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8ZF2ReEL8Eu1gp6GVaTtshS2yuMRLUMaC6puJGAg1QdVZlLK9QgzTw1AqNN0yn5MFfSf= XljB2RnmjcEz3SujlMB2dTo$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...GSP...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36568240 36228190 35578277 34768280 34548221=20
34608161 34768086 34528066 34028066 33118118=20
32718227 33058392 33598457 34108483 34498480=20
35498514 36548440=20

=3D =3D =3D
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AWUS01 KWNH 242255
FFGMPD
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-TNZ000-KYZ000-250430-

Mesoscale Precipitation Discussion 0229
NWS Weather Prediction Center College Park MD
654 PM EDT Sun May 24 2026

Areas affected...Upper Ohio Valley

Concerning...Heavy rainfall...Flash flooding likely

Valid 242253Z - 250430Z

SUMMARY...Repeating warm sector convection will continue to
develop and lift north-northeast through the Upper Ohio Valley and
western slopes of the Allegheny Plateau into the overnight. Hourly
rainfall rates of 1.5 to 2 inches over already saturated soils and
terrain of the western slopes will continue to allow scattered
flash flooding.

DISCUSSION...As of 23Z...A cold front is over western Ohio with a
persistent warm sector ahead over the upper half of the Ohio
Valley through the western slopes of the Allegheny Plateau and
expanding across western PA. Ample moisture with a gradient of
1.7" to 1.5" PW from south to north through the outlook area and
instability with 1500 J/kg SBCAPE along with deep layer SWly flow
of 35kt is allowing heavy bands to develop oriented close to their
direction of motion. Hourly rainfall estimates of 1.5 to 2" are in
the heaviest bands which has caused localized flash flooding given
low FFG from recent rains in these areas. This activity is
shifting farther east than recent days as the cool air damming
wedge breaks down, but slope/terrain increases, making the western
slopes of the Allegheny Plateau perpetually flash flood prone.
Furthermore, an MCV currently over eastern TN will lift up along
the KY/WV border this evening and potentially through WV
overnight.

Both recent HRRR/RRFS guidance have a decent handle on ongoing
activity and the threat this evening with generally 1-3" from the
western tip of VA through WV and western PA through 04Z. Given the
wet antecedent conditions and expectation for continued training
convection, any 1.5"+/hr rates will drive runoff concerns.
Therefore, scattered areas of flash flooding are likely to
continue into the overnight.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9Ee6HDoBOGzoITdAw2tENfQr1ELj1iyLRMcvdhVag7SS5goy0Al7_aDMhG0OgDuOlpKq= Y4Qkvys0FmS5bnVhVt20-hM$ for graphic product...

ATTN...WFO...CLE...CTP...ILN...JKL...LWX...MRX...PBZ...RLX...
RNK...

ATTN...RFC...ORN...RHA...TIR...NWC...

LAT...LON 41738049 41517924 40337887 39027941 37018106=20
36628195 36568323 36708410 37978340 39018265=20
40088245 40768222 41218174 41498134=20

=3D =3D =3D
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AWUS01 KWNH 250123
FFGMPD
FLZ000-GAZ000-ALZ000-250630-

Mesoscale Precipitation Discussion 0230
NWS Weather Prediction Center College Park MD
921 PM EDT Sun May 24 2026

Areas affected...North Florida

Concerning...Heavy rainfall...Flash flooding possible

Valid 250120Z - 250630Z

SUMMARY...Thunderstorms continue to develop along a trough over
the Florida Panhandle into North Florida well into the overnight.
Rain rates of 2 to locally 3"/hr will continue with the axis
nearly stationary. Localized flash flooding is possible overnight.

DISCUSSION...As of 03Z...Scattered thunderstorms continue to
develop over the FL Panhandle with a cluster of heavy
thunderstorms near Gainesville that continue to propagate
northwest. Abundant Gulf moisture and instability streaming in on
15kt southerly low level flow will continue to converge along the
trough axis. The PW is 2.2" along this trough with SBCAPE in a
tight gradient to low over southern GA (where there was earlier
organized activity) to 2500 J/kg along the FL Panhandle shore and=20
over North FL. This will continue to support activity. Earlier
heavy rain has lowered the FFG some which will allow localized
flash flooding.

Recent HRRR runs are higher in QPF than the RRFS with signs that
the Gainesville activity should work its way toward the Big Bend.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Efh_Ls21fUlXmBXpher_Wht893F0JVwkO45lEwXnqPXgVUmQ01Z217okaioHo3IGhfU= ZVvnVQmhelHrCNVlqiDCP8A$ for graphic product...

ATTN...WFO...JAX...MOB...TAE...TBW...

ATTN...RFC...ALR...NWC...

LAT...LON 31368501 31078366 30518230 29548194 29318252=20
29748296 30138390 30158501 30318548 30638650=20
31268651=20

=3D =3D =3D
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AWUS01 KWNH 250301
FFGMPD
TXZ000-251300-

Mesoscale Precipitation Discussion 0231
NWS Weather Prediction Center College Park MD
1100 PM EDT Sun May 24 2026

Areas affected...Central Texas....

Concerning...Heavy rainfall...Flash flooding possible

Valid 250800Z - 251300Z

SUMMARY...Numerous very intense but narrow downdrafts capable of
2"/hr rates have limited cell motions to support focused areas of
heavy rainfall that may result in localized flash flooding.

DISCUSSION...GOES-E WV suite depicts a very mature closed low in
the Heart of Texas toward the northeast Hill country. At 250mb,
the low is tilted from the 500mb center to the northwest to
provide solid down-shear divergence aloft and broad scale ascent.
In the low levels, proximity to the low has cyclonic convergence
but the winds are fairly light at 5-15kts at best. However,
originating convection across the Dallas/Fort-Worth Metro,
supported a cold pool and associated outflow boundary that has
remained strong enough to support convergence to activate updrafts
along the leading edge.

RAP analysis notes that capping is starting to win out with loss
of heating, yet a small pocket of conditionally unstable air with
CAPE values in the 1500 J/kg range from Runnels to Bell/N Burnett
county. Deep layer moisture (including through the typically
drier 700-500mb layer, as noted in CIRA LPW) is aligned to support
1.5" total PWats. As such, the favorable broad scale ascent and
the outflow are supporting numerous narrow updrafts in the region,
with solid longevity history as noted from older convection that
had originated the boundary... so scattered updrafts of 1.5-2"/hr
rates have lingered with near zero steering flow or limited enough
to help for some small collisions allowing for these highly
focused incidents of 2-3" totals in 1-2 hours.=20

Instability should be waning through the overnight period and the
outflow boundary should weaken as well, reducing coverage but the
risk remains for a few more hours overnight to suggest a few
incidents of flash flooding will remain possible especially as the
development continues to drift into lower FFG, near the San Saba
River Valley and the northeast Hill Country.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8Y3YR0tiPwDJDIw6tLQAvXTnBSxF3Qbu5O-7weB15ga5P3ED2ARACzG3X3s98imAx0yU= KbualKBgssB2SpQgHlIeb7I$ for graphic product...

ATTN...WFO...EWX...FWD...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32439886 32419838 32279789 31949754 31399750=20
31049781 30909829 30919879 31059917 31369949=20
31789957 32179934=20

=3D =3D =3D
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AWUS01 KWNH 250935
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-251500-

Mesoscale Precipitation Discussion 0232
NWS Weather Prediction Center College Park MD
534 AM EDT Mon May 25 2026

Areas affected...Southeast Louisiana...Southern
Mississippi...Southern Alabama...Western FL Panhandle...

Concerning...Heavy rainfall...Flash flooding likely

Valid 250935Z - 251500Z

SUMMARY...Intense, slow moving thunderstorms capable of 2-3"/hr
rates crossing saturated grounds may result in localized rapid
inundation flooding through early morning.=20

DISCUSSION...A very favorable mid to upper level dynamics pattern
continues to reside across the Central Gulf Coast region this
morning with ample warm/moist low-level moisture to support highly
efficient deep warm cloud showers and thunderstorms. GOES-E WV
suite shows a deep layer, nearly stacked closed low over central
Texas with an impressive anticyclonically curved upper-level
cirrus across the Lower Mississippi Valley indicative of right
entrance but also diffluent right quadrant jet ascent pattern in
advance of a potent shortwave feature lifting north along 90W.=20
This provides multiple favorable upper-level features for broad
scale ascent but also effective evacuation for shower/thunderstorm
activity to develop organized convective clusters/bands through
this morning.

There will be a more than sufficient deep moisture pool supported
by early morning Gulf 'exhalation' of surface latent heat to
provide surface warming/low level profile saturation to enhance
instability given mostly narrow, skinny profiles with lapse rates
below 6C/km; still with 12-13Kft of warm profile and stacked
moisture plumes per CIRA LPW layers supporting 2"+ Total PWat
values. So, currently the MLCAPEs are sufficient for 1000-1500
J/kg, efficient warm cloud, heavy rainfall production.

Moisture flux convergence will be increasing with low level backed
easterly to southeasterly flow off the warm north-central Gulf,
while quickly veering to the south and southeast above the surface
to 700mb. The deep layer convergence will further aid rainfall
production with moderately wide updrafts being capable of
2-2.5"/hr rates, though may occasionally uptick to 3", especially
near coasts where frictional convergence can support
back-building/regenerative flanking development. Further east
across Mobile Bay to W FL, the activity may be a bit less in
coverage given more easterly low level flow reducing that
frictional support compared to SE LA into S MS.

Residency is a bit more uncertain, but deep layer flow in
proximity to the south to north passing shortwave should support
some repeating/training elements, so spots of 3-5" are probable,
with a solid suite of Hi-Res CAMS hinting at some isolated spot or
two of greater than 7". While most of the area is sandy or swampy
in nature, recent heavy rainfall has fairly saturated the upper
soils with 0-40 cm ratios over 70% with some spots over 80%; so
way over the 95-97th percentiles (spots at maximum). As such,
infiltration even at 'normal' intensities (1.5-1.75"/hr) could
result in rapid inundation flooding. While the entire area of
concern is clearly not likely to experience flash flooding, there
are many locations that will, with some isolated to widely
scattered considerable flash flooding possible especially if
aligned with the urban centers, like NOLA or the MS coastal towns.
As such, flash flooding is considered likely for this MPD through
15z.



Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8JZZzdAB8ExsIMjG_ep-LcRdmT_dBYdbZvCN3Oe8qD2n3ue02-Zp6TeMKA1qwpjoNZbb= 87co7tB1gSmQBJ1tsxdgBOo$ for graphic product...

ATTN...WFO...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 31698881 31658796 31438735 30858679 30418662=20
30278711 30148774 30068863 29258893 28868916=20
29048984 28959102 29959086 30849031 31498974=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 251246
FFGMPD
TXZ000-251645-

Mesoscale Precipitation Discussion 0233
NWS Weather Prediction Center College Park MD
845 AM EDT Mon May 25 2026

Areas affected...central TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 251244Z - 251645Z

SUMMARY...Isolated flash flooding will be possible across portions
of central TX with slow moving showers/thunderstorms. Hourly
rainfall of 1 to 2 inches (locally higher possible) and totals of
2 to 4+ inches are expected through 16Z to 17Z.

DISCUSSION...1220Z radar imagery showed a remnant MCV located
between Comanche and Eastland, TX with convection that continued
to regenerate over Coleman, Brown, Callahan and Eastland counties.
Elevated instability of 500-1000 J/kg was estimated via RAP
analysis data to exist within a narrow corridor just southwest of
the MCV circulation with low level southerly flow allowing the
advection of instability northward, into the western half of the
MCV circulation, helping to feed the renewed development of
thunderstorms. Flow aloft was modestly divergent and diffluent,
helping to support lift over the region. A slow westward drift of
the MCV is forecast by the RAP through 18Z which will likely
continue to support localized slow moving cores of heavy rain
(5-15 kt motions) capable of producing 1 to 2 inches of rain in an
hour (locally higher). Additional rainfall totals of 2 to 4+
inches are expected through 16 to 17Z at which point, daytime
heating and deepening of the boundary layer may act to disrupt the
ongoing activity.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5xztdNf3NdPkqFbN0Pv7JvqYj3HAy7zPrQTEqT6YjuEgj_VqSP5oyE5T_q-XqyGJgK7F= 9TB22crcmUC8MINV6C-SMPw$ for graphic product...

ATTN...WFO...FWD...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32989917 32509854 31919827 31499839 31089874=20
31069960 31949999 32759978=20

=3D =3D =3D
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AWUS01 KWNH 251519
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-252100-

Mesoscale Precipitation Discussion 0234
NWS Weather Prediction Center College Park MD
1118 AM EDT Mon May 25 2026

Areas affected...central Gulf Coast into eastern MS/western AL

Concerning...Heavy rainfall...Flash flooding likely

Valid 251518Z - 252100Z

SUMMARY...At least localized areas of flash flooding will be
likely across portions of the central Gulf Coast into eastern MS
and western AL through 21Z. Areas of training thunderstorms will
be capable of 2 to 3 in/hr rainfall and given saturated soils,
areas of flash flooding are expected through the remainder of the
morning into the afternoon.

DISCUSSION...Regional radar imagery at 15Z helped identify a
couple of MCVs within an area of scattered thunderstorms extending
from southeastern LA, southern MS and the western FL Panhandle,
northward into eastern MS and western AL. The environment was
represented by 12Z soundings from LIX and JAN (along with 14Z SPC
mesoanalysis data) showed MLCAPE of ~500 to 1000 J/kg along with
PWs near 2 inches. Ascent across the larger scale environment was
favorable for heavy rain with low level flow sandwiched between a
700-500 mb low over eastern TX and a ridge off of the southeastern
U.S., located beneath the divergent right-entrance region of an
upper level jet positioned over the lower MS and lower OH Valleys.

There is currently a relative minimum in MLCAPE over central to
northern MS which should limit rainfall intensities with northward
extent but pockets of higher MLCAPE exist to the south and east
(into western AL). In addition, areas of increasing instability
will be possible through some degree of surface heating among
areas of thick cloud cover, supportive of intense rainfall via
dominant warm rain processes. N to NNE movement of the two MCVs
will continue as well as additional thunderstorms approaching from
the northern Gulf with potential for MCV development. Areas of
training are expected with high hourly rainfall of 2 to 3 inches
at times. These high rain rates along with mostly saturated soils
due to rainfall over the past week will likely allow for at least
isolated areas of flash flooding through 21Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_djEPrzdmxZ8H-zvzUY2jrIMdPGkkiyW6lA-eGZhyLu3YWMfAUYPJrvUE5YfYuRjF56c= d-CAYqgx8EeSYhhGntfA0Ac$ for graphic product...

ATTN...WFO...BMX...JAN...LIX...MEG...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 33968788 33608737 32798698 31738695 30298720=20
29428788 28768897 28839023 30079032 31798989=20
32438966 33888885=20

=3D =3D =3D
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AWUS01 KWNH 251748
FFGMPD
TXZ000-252315-

Mesoscale Precipitation Discussion 0235
NWS Weather Prediction Center College Park MD
147 PM EDT Mon May 25 2026

Areas affected...central to western TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 251745Z - 252315Z

SUMMARY...Isolated to widely scattered flash flooding will be
possible through 23Z across parts of central to western TX. Slow
moving thunderstorms will be capable of producing hourly rainfall
of 1 to 2+ inches along with totals of 2 to 4+ inches.

DISCUSSION...Visible satellite imagery from 1720Z showed a field
of deepening cumulus clouds over portions of the Edwards Plateau,
northwestward into the Rolling Plains region of west-central TX.
Cloud streets identified confluent low level flow into the region,
located west of a remnant MCV located roughly 40 miles east of
Brownwood. A lack of cumulus inferred stability near the MCV
center from prior rainfall, but estimated MLCAPE of 1000-2000 J/kg
was shown via the 17Z SPC mesoanalysis amid weakly anomalous PW
values over central to western TX.

Thunderstorm coverage is expected to increase through the
remainder of the afternoon to the southwest and west of the slow
moving (nearly stationary) MCV with some component of left-exit
region upper level divergence aiding with broader scale ascent
across central TX. The greatest concern for isolated to widely
scattered flash flood coverage through 23Z is with slow movement
of cells (5-15 kt) coupled with portions of the state that have
picked up 300 to 600 percent of normal rainfall over the past
week. Slow cell motions will likely yield hourly rainfall of 1 to
2 inches (locally higher) which may result in isolated totals of 2
to 4+ inches. Local runoff sensitivities of the Hill Country and
possibly as far east as I-35 near San Antonio are also
considerations into the afternoon.=20

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6yWpBt9U5fD3K9mNbvCfvsFn4cJ4wr-N3sjqGqu6sRDlWZmItqaZgNzRvksxeraZstgl= 76yHsj8Hy6CvenkR4FwUeS4$ for graphic product...

ATTN...WFO...EWX...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32890077 31909993 30899845 29999804 29359854=20
29490010 30240156 31280221 32230221 32880173=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 251859
FFGMPD
AZZ000-260045-

Mesoscale Precipitation Discussion 0236
NWS Weather Prediction Center College Park MD
257 PM EDT Mon May 25 2026

Areas affected...Central and Northern Arizona

Concerning...Heavy rainfall...Flash flooding possible

Valid 251857Z - 260045Z

SUMMARY...Slow-moving, pulse-type convection driven by an
upper-level low will produce localized but occasional intense
rainfall rates. While regional soils are exceptionally dry, these
intense rates over steep terrain, locally hydrophobic soils, and
potential burn scars will make highly localized flash flooding
possible through this evening.

DISCUSSION...Regional radar and GOES-West WV imagery this
afternoon depict a relatively moist and unstable environment
across central and northern Arizona, driven by a slow-moving
upper-level low. The cold core associated with this upper low has
established steep mid-level lapse rates. Despite a dry sub-cloud
layer, continued surface heating has yielded SBCAPE values in the
1000-1500 J/kg range. Concurrently, a somewhat anomalous moisture
plume has pushed PWATs to around 0.75 inches which is more than
sufficient for locally heavy rainfall rates when combined with the
instability across this high-elevation environment.

Given the proximity of the upper low, the kinematic environment is characterized by very weak effective bulk shear (generally <20
kts) and weak deep-layer mean steering flow. This is resulting in
a pulse convective mode with nearly stationary or erratic,
slow-moving cells. Recent MRMS data indicates these cells are
somewhat efficient after initially moistening the column, and are
dropping 0.25 to 0.50 inches of rain in 15-minute intervals
(equivalent to 1-2 in/hr rates) before the updrafts collapse. The
12Z HREF/REFS guidance highlights a 20-30 percent probability of
exceeding local Flash Flood Guidance (FFG) and 1 in/hr rates, with
a few HREF members suggesting localized totals could approach or
exceed 2 inches where cells anchor or merge.

While NASA SPoRT soil moisture and USGS streamflow data indicate
the region is exceptionally dry, the desert environment in this
region is highly sensitive to short-duration, high-intensity
rainfall. The baked, rocky terrain will tend to promote enhanced
runoff with these higher rainfall rates. The flash flood threat
will be notably isolated, but rather acutely focused on normally
dry arroyos, slot canyons, and steep terrain along or near the
Mogollon Rim. Furthermore, any stationary cores that develop over
recent burn scars will carry a risk for debris flows and channel
runoff.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9Z0ytRndCSgoeOo8m_k2qFUhQ2f-yoYzHuLybsphvRaLsm3FOZjaEx4UpC_2xRQUvSp3= 59y3695oDF01uBWybj8A6Lo$ for graphic product...

ATTN...WFO...FGZ...PSR...TWC...VEF...

ATTN...RFC...STR...NWC...

LAT...LON 36601203 35841076 34761005 33610997 33171079=20
33821223 34191327 35001403 35871416 36531349=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 251955
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-260145-

Mesoscale Precipitation Discussion 0237
NWS Weather Prediction Center College Park MD
353 PM EDT Mon May 25 2026

Areas affected...Northeast Alabama...Central and Northern
Georgia...Central and Upstate South Carolina

Concerning...Heavy rainfall...Flash flooding likely

Valid 251953Z - 260145Z

SUMMARY...Deep convection will continue to expand in coverage and
intensity this afternoon and evening, driven by a surface boundary
across Georgia/South Carolina and a northward-lifting MCV over
Alabama. Intense rainfall rates exceeding 2 in/hr, coupled with
relatively slow storm motions and highly sensitive urban
corridors, will make flash flooding likely.

DISCUSSION...Regional radar and satellite imagery this afternoon
highlights an expanding footprint of deep convection across the
interior Southeast. Across west-central Georgia through central
South Carolina, activity is focusing along a surface trough and
pronounced instability gradient. Further west, a well-defined MCV
is noted over central AL in visible satellite images steadily
lifting northward.

The mesoscale environment ahead of both of these forcing
mechanisms is highly favorable for extreme rainfall efficiency.
The airmass is characterized by pooling PWATs of 1.8 to 2.0 inches
and MLCAPE values surging into the 1500-2500 J/kg range in the
warm sector. Shear is rather modest with effective bulk shear
generally 20 to 30 kts at best, so much of the convective threat
will tend to remain rather disorganized. Regardless, the pulse and
localized multicell convection will be capable of high rainfall
rates approaching or exceeding 2 in/hr which has already been
confirmed with recent MRMS data.

Given the high rainfall rates and presence of weak steering flow,
there will likely be additional areas of convective persistence
that will support scattered areas of excessive rainfall. The
latest HREF and REFS guidance suggests additional pockets of 2 to
4+ inch rainfall totals going through this evening.

NASA SPoRT soil moisture data and USGS streamflow analyses suggest
areas of sensitivity from recent rainfall, and these additional
rains this afternoon and this evening will promote concerns for
runoff issues. Scattered areas of flash flooding will tend to be
likely, and this will also include concerns by this evening around
the Atlantic metropolitan area.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4EgtUFe52QEX3VP6WsJj9zairWX8Fws5uI6et4v-hMOWC6et8UFG-dcq0hLQ25MJF1t_= g4Rx2VhG9_k1aEn7tnShd3E$ for graphic product...

ATTN...WFO...BMX...CAE...CHS...FFC...GSP...HUN...MRX...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 35118486 34998426 34778347 34778274 34618183=20
34318120 33538120 32908155 32378229 32298323=20
32438402 32738471 33308560 33518618 33808686=20
34258708 34778689 35068602=20

=3D =3D =3D
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AWUS01 KWNH 252049
FFGMPD
FLZ000-TNZ000-ALZ000-MSZ000-260245-

Mesoscale Precipitation Discussion 0238
NWS Weather Prediction Center College Park MD
447 PM EDT Mon May 25 2026

Areas affected...Mississippi...Alabama...Florida Panhandle

Concerning...Heavy rainfall...Flash flooding likely

Valid 252047Z - 260245Z

SUMMARY...Multiple Mesoscale Convective Vortices (MCVs) embedded
within a deep tropical airmass will continue to drive rounds of
heavy showers and thunderstorms through this evening. Intense
rainfall rates of 2 to 3 in/hr, combined with wet antecedent
conditions and cell-training concerns, will result in localized
additional totals of 3 to 5 inches. Flash flooding is likely.

DISCUSSION...Regional radar and satellite imagery late this
afternoon show widespread, deep convection persisting across
sizable areas of Mississippi, Alabama, and the Florida Panhandle.
The mesoscale environment remains exceptionally favorable for
highly efficient, tropical-like rainfall production. Recent RAP
mesoanalysis indicates PWAT values ranging from 1.8 to over 2.1
inches pooling along and inland of the Gulf Coast, juxtaposed with
a broad axis of 1000-2000 J/kg of MLCAPE. This is fostering a deep
warm cloud layer capable of sustaining extreme rainfall rates,
which recent MRMS data confirms are occasionally reaching 2 to 3
in/hr.

The kinematic forcing is being driven by multiple compact MCVs
lifting northward through the deep-layer southerly flow. A
persistent axis of moisture transport and convergence is
continuously feeding these features. The presence of these
boundaries, combined with relatively weak upwind propagation
vectors, is heavily favoring periods of backbuilding and
cell-training.

Going through the evening hours, the latest high-resolution
ensemble guidance (including the HREF and REFS), as well as recent
HRRR and RRFS iterations, are in strong agreement that portions of
this convective axis will be maintained. The CAM consensus
suggests additional localized rainfall totals of 3 to 5+ inches
are likely wherever training bands anchor. Given the wet
antecedent conditions and lowering Flash Flood Guidance (FFG)
across the region, this additional intense rainfall will likely
favor additional regional concerns for flash flooding. A localized
instance or two of significant flash flooding cannot be ruled out
if some of these rains anchor over the more sensitive urban areas.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4jTEwZrlWt1QNdginnGSyxpxeA8gazGmcZIBu2sFIT7X1o6PYIpbyzs4qD3dkl_yfNyu= ifRl3i27V8J8qArZbiP-7YY$ for graphic product...

ATTN...WFO...BMX...HUN...JAN...MEG...MOB...OHX...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 35198758 34788670 34078624 32478551 31188528=20
30008551 29728635 30078754 30548794 31428834=20
32058886 33318963 34008972 34678934 35168843=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 252128
FFGMPD
VAZ000-NCZ000-TNZ000-260325-

Mesoscale Precipitation Discussion 0239
NWS Weather Prediction Center College Park MD
526 PM EDT Mon May 25 2026

Areas affected...Western North Carolina...South-Central to
Southeast Virginia

Concerning...Heavy rainfall...Flash flooding likely

Valid 252126Z - 260325Z

SUMMARY...Heavy showers and thunderstorms will continue to impact
south-central and southeast Virginia, while new convection
develops across western North Carolina this evening ahead of a
slow-moving cold front. Intense rainfall rates of 2 to 3 in/hr,
combined with some cell-training, will yield localized totals of 3
to 5 inches. Extreme rainfall rates may overpower dry antecedent
soils, making flash flooding likely which will include urban
corridors.

DISCUSSION...Late-day satellite and radar imagery depicts an axis
of intense, and locally training convection currently impacting
portions of south-central and southeast Virginia, including the
sensitive I-64 corridor from Richmond down through Hampton Roads.
This activity is tapping into a deeply anomalous, tropical-like
airmass characterized by PWATs pooling between 1.8 and 2.0 inches
and MLCAPE values of 1000-1500 J/kg. The immediate forcing over
this Virginia corridor is being driven by a stacked, high-end
couplet of strong 850mb convergence and 250mb divergence.

Further southwest, an upstream cold front approaching slowly from
the northwest will interact with this same unstable, moisture-rich
airmass going through the evening hours. This will trigger a
separate and potentially focused area of convection across the
Piedmont region of western North Carolina.

Kinematically, the environment across both target areas is primed
for organized, repeating rounds of heavy rainfall. Effective bulk
shear of 25 to 35 kts will maintain persistent multicell clusters,
while upwind propagation vectors oriented parallel to the
respective forcing boundaries will strongly favor cell-training.
The deep warm cloud depths will support highly efficient rainfall
rates of 2 to 3 in/hr. Consequently, the 18Z high-resolution
ensemble suite (HREF and REFS) strongly supports localized
rainfall totals of 3 to 5 inches through the evening.

While recent soil moisture data indicates dry antecedent
conditions across portions of the Mid-Atlantic, rainfall rates of
2 to 3 in/hr will likely exceed the maximum infiltration capacity
of the soils, resulting in potential for rapid runoff. The flash
flood threat is currently highest across the low-lying, densely
populated urban footprint of south-central and southeast Virginia,
but will concurrently increase across some of the Piedmont areas
of western North Carolina as the frontal boundary approaches
tonight.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_KRj4u6Q8wMtfB_QElWVybn108hHZT4bvXUNkuCeg2dZFejvW_LK8PqdYhXCtP1XtIkp= 7D7J9nv5gRq3nkD9_tjVaG8$ for graphic product...

ATTN...WFO...AKQ...GSP...LWX...MRX...RAH...RNK...

ATTN...RFC...ALR...ORN...RHA...TIR...NWC...

LAT...LON 38097699 37837609 37297578 36817594 36567658=20
36367791 35947992 35328163 35208272 35558286=20
35948237 36278181 36708069 37187958 37837819=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 252212
FFGMPD
TXZ000-260230-

Mesoscale Precipitation Discussion 0240
NWS Weather Prediction Center College Park MD
611 PM EDT Mon May 25 2026

Areas affected...Central Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 252211Z - 260230Z

SUMMARY...A compact, slow-moving Mesoscale Convective Vortex (MCV)
will continue to trigger scattered thunderstorms into this
evening. Weak steering flow will lead to slow storm motions and
localized rainfall rates of 1 to 2 in/hr. While coverage remains
limited, this activity will make highly localized, primarily urban
flash flooding possible.

DISCUSSION...Late-day GOES-E visible satellite imagery along with
radar depicts scattered, slow-moving thunderstorms continuing to
initiate across north-central into central Texas. This activity is
being driven by a stubborn, compact 500mb MCV currently spinning
over the region. The mesoscale environment is characterized by
pooling deep-layer moisture (PWATs of 1.5 to 1.7 inches)
juxtaposed with moderate to strong instability (MLCAPE values of
1500-2500+ J/kg).

While the thermodynamic environment is supportive of efficient
rainfall, the primary driver of the flash flood threat is the
kinematic profile. Effective bulk shear is exceptionally weak
(generally under 20 kts), and upwind propagation vectors are
nearly zero. Consequently, any initiated updrafts are exhibiting
very slow, erratic motions. Recent MRMS data indicates these
nearly stationary cores are successfully producing localized
rainfall rates of 1 to 2 in/hr.

Despite the favorable mesoscale setup for heavy rain, overall
convective coverage remains relatively limited, and
high-resolution guidance suggests some uncertainty regarding how
far into the evening hours this activity will persist before
diurnal stabilization takes over. However, given the trajectory of
the MCV, the convective footprint encompasses the sensitive
Dallas-Fort Worth metropolitan area on down through Waco and
Austin. At least eastern portions of the rocky, runoff-prone
terrain of the Hill Country are also included in the threat area.
Therefore, while widespread issues are not anticipated, isolated
instances of flash flooding remain possible through the
mid-to-late evening hours.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6IaTPwDXvDK6JTj3RYxDje9CGvQ0WIt4k-mDctHEHhpGFndDR3ZRfnHabf3cPfaQQfV9= gkUhLFcnYDcYtoB_gQuvqno$ for graphic product...

ATTN...WFO...EWX...FWD...HGX...

ATTN...RFC...FWR...NWC...

LAT...LON 33359722 32419631 31329612 30359669 29809787=20
29789869 30269905 31069825 31809806 32569831=20
33259815=20

=3D =3D =3D
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AWUS01 KWNH 260104
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-MSZ000-260700-

Mesoscale Precipitation Discussion 0241
NWS Weather Prediction Center College Park MD
903 PM EDT Mon May 25 2026

Areas affected...Northern Alabama...Middle and Southeast
Tennessee...Northern Georgia...Far Upstate South
Carolina...Western North Carolina

Concerning...Heavy rainfall...Flash flooding likely

Valid 260103Z - 260700Z

SUMMARY...Efficient showers and thunderstorms will continue to
track across northern Alabama and into the complex terrain of the
southern Appalachians tonight. Forcing from a nearby synoptic
front and a translating MCV, combined with deep moisture, will
support rainfall rates of 1 to 2+ in/hr. Localized additional
totals of 2 to 4+ inches will make flash flooding likely.

DISCUSSION...Early-evening GOES-E IR satellite and regional radar
data shows an axis of highly efficient convection moving across
the southern Appalachians, intersecting portions of southeast
Tennessee, northern Georgia, and the western Carolinas. Further
west, a distinct Mesoscale Convective Vortex (MCV) positioned
along the AL/MS border continues to drive heavy rainfall across
northwest Alabama. Through the late evening hours, the forcing
associated with this MCV is expected to translate northeastward
across far northern Alabama and middle Tennessee, generally
merging with the ongoing convective threat over the higher terrain
of the Cumberland Plateau and southern Appalachians.

The mesoscale environment remains highly supportive of heavy,
sustained rainfall. A synoptic-scale front draped across the
region is interacting with 500 to 1000 J/kg of lingering MLCAPE,
providing continuous fuel to sustain the convective threat. This
is occurring within a deep tropical airmass characterized by
Precipitable Water (PWAT) values of 1.75 to 2.0 inches.
Furthermore, strong large-scale ascent is being provided by a
stacked couplet of 850mb convergence and 250mb divergence centered
over the region.

As the convection tracks generally northeastward, low-level flow
vectors are oriented to provide modest but persistent upslope
ascent into the higher terrain of the Cumberland Plateau and Blue
Ridge Mountains. This orographic forcing, combined with the deep
warm cloud layer and the synoptic/MCV lift, is yielding highly
efficient rainfall rates of 1 to 2 in/hr.

The latest high-resolution guidance (including recent HRRR
iterations) suggests that these intense rates will persist over
the next several hours, capable of depositing localized additional
rainfall totals of 2 to 4+ inches. Given the steep topography,
flashy nature of the local basins, and wet antecedent conditions,
rapid runoff is expected. Areas of flash flooding are already
ongoing, and additional flash flooding is expected over the next
several hours which will include rapid rises on small creeks,
streams, and low-water crossings.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5T5-tBUse90iIR8cAVDePjIh0Zu0ljH8pr00Wf99SAlbt0bovSxKulXsCvO9NuuEFdHx= wjsyULM0p6TK3s9fqZyFvR0$ for graphic product...

ATTN...WFO...BMX...FFC...GSP...HUN...MEG...MRX...OHX...RNK...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36328158 35768116 35158196 34768288 34408398=20
34108582 33718729 33878791 34268819 34908797=20
35248721 35538594 35648481 35938352 36208256=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 260202
FFGMPD
SCZ000-FLZ000-GAZ000-260700-

Mesoscale Precipitation Discussion 0242
NWS Weather Prediction Center College Park MD
1000 PM EDT Mon May 25 2026

Areas affected...Northern Florida...Eastern Georgia...Central
South Carolina...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260200Z - 260700Z

SUMMARY...Slow moving,back-building potential within very deep
moisture environment pose spots of 2-4" and possible widely
scattered incident or two of flash flooding.

DISCUSSION...CIRA LPW suite especially in the sfc to 700mb layers
shows a dual streams of confluence from the central Gulf into the
Northeast Gulf melding across the northern neck of Florida into
southeast GA, resulting in a plume of 2-2.25" total PWats with
solid deep layer convergence. Also, lower profiles show
sufficient heating for narrow skinny profiles and a wedge of
remaining 1500 J/kg. Aloft, anticyclonic curved right entrance of
upper level jet is also providing solid divergence aloft along the
confluence axis to help maintain updrafts. The deep layer
confluence does have some split above 700mb to allow for some weak
DPVA ascent to compliment the divergence aloft but given the
oblique nature at the far eastern influence of the closed
upper-low over Texas. As such, thunderstorm activity with
15-25kts of upstream speed max at 850mb, supports potential for
back-building, especially further south and likely to support
2-2.5"/hr rates.=20=20

With weak inflow, cell motions will also be diminished allowing
for greater residency time and highly focused but widely scattered
incidents of 2-4" totals. Sandy conditions across N FL into GA
have naturally higher FFG, but recent repeating days of convection
has lead to an increase in 0-40cm soil moisture values per NASA
SPoRT, as such; given these rates, a few incidents of
focused/localized flash flooding are considered possible.

While the moisture flux is reduced further north, the Piedmont of
SC has seen Total PWats up to 2.25" as well, and with slightly
deflected low level flow responding to the upper-level ridge aloft
and jet entrance to the northeast; a similar convective
environment/potential exists as well. The main difference is the
naturally lower FFG and prone areas along the Fall-line in central
SC, so even with less rainfall rates/potential than further south,
the hydrology will be easier to exceed given the moisture
availability.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8mQciNTb-G1-PUEUKuF1u8CSN3ePK5WYz5ABJeJy2W46RextCdQHU5rnAfQyUgMIgStx= KLx_dLBYWOj5kGNQFI30Vaw$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...JAX...

ATTN...RFC...ALR...NWC...

LAT...LON 34508120 34268053 33018137 31938176 31008181=20
29928183 29918258 31708291 32478299 33288286=20
33958197=20

=3D =3D =3D
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AWUS01 KWNH 260248
FFGMPD
TXZ000-NMZ000-260830-

Mesoscale Precipitation Discussion 0243
NWS Weather Prediction Center College Park MD
1047 PM EDT Mon May 25 2026

Areas affected...Southeast New Mexico...Western Texas Cap Rock...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260245Z - 260830Z

SUMMARY...Strong moisture flux convergence will support up to
1.5"/hr rates with slowly advancing convective complex. Localized
totals of 2-3" may produce localized flash flooding conditions
overnight.

DISCUSSION...GOES-E WV shows the larger scale closed low over the
San Francisco Plateau of northern Arizona with broad/strong
southwesterly flow along the southern periphery. Embedded within
the weakly negative tilt trough is a tight vorticity/shortwave
center that is well depicted in both WV and regional RADAR suite
in the Rio Grande Valley near KHMN. The speed shear and vorticity
is providing a strong upslope component along the lee of the
Sacramento Mtns with a pair of surface low near Roswell and
Carlsbad, with both having very high directional convergence along
it (with northerly winds from NE NM and strong SE winds across the
Pecos River Valley). Surface to boundary layer moisture is
limited to mid to upper 40s Tds, but the CIRA LPW shows pool of
enhanced banked up moisture in two lowest layers (850-700,
700-500mb layers) providing total PWats into the 1" range
currently. However, the strength of low-level flux through the
Pecos Valley will be increasing throughout the early overnight
period.=20

Given the strong dynamics aloft and very convergent low levels,
moisture flux is starting to support 1.25-1.5"/hr rates, given
10.3um EIR shows complex cooling to -65C to -70C. As such, a
convective complex is maturing over eastern and southeastern NM;
with initial convective cells upscaling and merging into larger
clusters and eventually a complex over the next few hours. This
should allow for increased residency time and an area of 2-3"
totals can be expected.

Very dry/hard grounds with naturally high FFG values may help to
mitigate broader flash flooding conditions, but given the
intensity with localized bursts during mergers, localized flash
flooding conditions may arise though the evening. Eventually a
cold pool should develop and the complex should start to advance
eastward, likely quickly given very strong propagation vectors
given increasing east-southeast surface to 850mb flow over 40kts,
so potential will diminish with time.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4fgCMyy8vR0xzYHXBC1an4ca8CQbZrr1azdB1mxEaW-d3yoN7MDlvuwc6YyedyuSuo4H= P4yo_9ImXhMmtXY3E1UFUIc$ for graphic product...

ATTN...WFO...ABQ...LUB...MAF...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 35390454 35270374 34760308 33980244 32760234=20
31960297 31980411 32440459 33070493 33400507=20
34280521 35070504=20

=3D =3D =3D
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AWUS01 KWNH 260332
FFGMPD
TXZ000-NMZ000-260900-

Mesoscale Precipitation Discussion 0244
NWS Weather Prediction Center College Park MD
1131 PM EDT Mon May 25 2026

Areas affected...Western Texas Panhandle...Pecos River Valley...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260330Z - 260900Z

SUMMARY...Fast moving, but increasing intense rainfall rates with
Sub-hourly totals of 1", resulting in quick run-off and possible
localized flash flooding incident or two overnight.

DISCUSSION...GOES-E 10.3um EIR denotes a expanding line of
scattered thunderstorms increasing/cooling across the central
portion of the Western Texas Panhandle spurred on by rapid
height-falls from an ejecting shortwave in south-central NM within
a broader base of the large scale trough centered in N AZ. The
broad southwesterly flow crossing terrain has resulted in a very
strong lee-pressure trough across much of eastern NM to a surface
low near ROW; however, behind the main S/W lifting out, the
surface trough then angles southwest into Hudspeth county and
northern Chihuahua denoted well by some low-level warmer topped
agitated Cu/Tcu.=20

Strong response in the low-levels with up-slope winds steadily
increasing past 30kts on their way to 40kts is helping convective initiation/development two fold. The initial is the strong mass
convergence that extends along the entire surface trough to break
out these scattered cells, the second is increasing moisture
transport, Tds has steadily increased into the low 50s, but low
60s and sfc-850mb LPW (up to .75") is coming up the Rio Grande and
Pecos River Valleys to intersect the initial convective round.=20
Not surprisingly given proximity to the elevated desert plateau,
steep lapse rates are supporting increasing instability values as
the higher theta-E air pushes in to allow for strong vigor of
updrafts and moistening the columns. Currently rates are minimal
due to evaporative loss, but as the overall moisture arrives, flux
convergence will support intense rainfall rates capable of
.5-.75"/15 minutes (per HRRR). While forward propagation will be
equally fast and reduce overall totals, localized spots of 1.5"
are possible in about 1hr and the harder ground conditions will be
difficult for infiltration at those rates suggesting localized
flash flooding is possible tonight.

While a bit less certain, there are suggestions, given strong
southwesterly flow and embedded mid-level impulses and expected
limited eastward movement of the surface trough, additional
development may be possible to allow for a secondary round to
occur later in the period, with best potential further north along
the TX/NM east-west boarder. Will continue to monitor those
trends for any subsequent MPD necessity.=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9FNM9rT40AmTjVu5cmW52AF9sGiR5_3d2Of1w2kKCglVD0tRAxRvfMMl-jWI1Or9gwXh= RsRIcxYae3EMWh1O5hqfY6c$ for graphic product...

ATTN...WFO...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 32340317 32170238 31690186 30950168 29930199=20
29640258 29250280 28960324 29300415 29730461=20
30450487 30810489 31600479 32050416=20

=3D =3D =3D
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AWUS01 KWNH 260420
FFGMPD
FLZ000-GAZ000-ALZ000-260900-

Mesoscale Precipitation Discussion 0245
NWS Weather Prediction Center College Park MD
1219 AM EDT Tue May 26 2026

Areas affected...Western GA...Central FL Panhandle...Far Eastern
AL...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260420Z - 260900Z

SUMMARY...A few more hours of potential training, highly efficient
convection capable of 2.5"/hr and a streak or two of 2-4" totals
resulting in possible localized flash flooding.

DISCUSSION...Regional RADAR and 10.3um EIR from GOES-E continue to
show flare-ups of convection along the eastern edge of the warm
conveyor belt which appears to be at the near eastern limit of
influence from the parent larger-scale decaying closed low in
Eastern Texas. The warm conveyor continues to pump enhanced
moisture through a deep fairly unidirectional south to north
stream from the east-central Gulf northward along the AL/GA line.=20
An equally narrow axis of instability remains along the eastern
edge of the q-axis with solid overlap. Surface easterly flow has
recently intersected the north-south boundary and new convection
has developed along it. Given upstream elongated vorticity
strip/shortwave over the north-central Gulf lifting north,
combined with weak to moderate divergence at the entrance to the
northeastward angling upper-level jet streak across the southern
Appalachians, will help to maintain any of these localized low
level convergence maxima that spark another round of convection;
this included southerly frictional convergence at the Gulf/Florida
Panhandle interface, especially as the sfc convergence retrogrades
west deeper into the q-axis.=20=20

Total PWat values of 2-2.25" and narrow skinny CAPE profiles (up
to 1500 J/kg) with 20-30kts of LLJ inflow/flux convergence has and
will likely to aid 2-2.5"/hr rates and with stronger flow off the
Gulf, flanking line redevelopment can support back-building edges
parallel to the deep layer steering allowing for localized 2-4"
localized streaks. This may result in an incident or two of
localized rapid inundation/flash flooding for prone areas and
intersected urban centers. All in all, flash flooding is
considered possible in an isolated to widely scattered manner
through the overnight period.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9ekI4s4N01qIcb5We4Ud44vJvUYrxfAOp9zKbFmiR7DjkOR4jEx9_2Xddijm-z7h5JET= VsFEEAUgwV3dIf5LkCaWdr0$ for graphic product...

ATTN...WFO...BMX...FFC...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 33998513 33908435 33198409 32078397 31038404=20
29738461 30228605 31658572 32568554 33148547=20
33788539=20

=3D =3D =3D
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AWUS01 KWNH 260827
FFGMPD
TXZ000-NMZ000-261400-

Mesoscale Precipitation Discussion 0246
NWS Weather Prediction Center College Park MD
426 AM EDT Tue May 26 2026

Areas affected...Southeast New Mexico...Portions of the Cap Rock,
Permian Basin and Trans-Pecos Regions of Texas...

Concerning...Heavy rainfall...Flash flooding possible

Valid 260830Z - 261400Z

SUMMARY...Main cluster to maintain/enhanced through early morning
with hourly rates of 1-1.5"/hr and additional 2-3" totals, with
continued incidents of localized flash flooding possible.

DISCUSSION...GOES-E WV suite depicts closed low tightening a bit
over NE AZ with broad southwesterly flow across its southeast
quadrant starting to lift with veering 500mb winds enhancing
larger scale DPVA across the Rio Grande into Pecos River Valleys
over the next few hours. This will help to broaden diffluence and
dual jet divergence pattern across SE NM into the eastern portions
of the W Texas Panhandle. The combination will help to
maintain/evacuate the expanding convective cluster across SE NM
moving into the W Texas portion of the Permian Basin.=20=20

Low-level jet response remains strong with 30-40kts of
southeasterly flow generally orthogonally intersecting the
rainfall reinforced surface trof/isentropic ascent boundary that
extends from a surface low east of Hobbs back west northwest of
the Davis Mtns through southern Hudspeth county though surface to
850mb flow is further backing south across the Big Bend due to
strengthening surface to 850mb near the National Park. Tds into
the upper 50s/lower 60s are now intersecting the boundary and
helping to maintain the main cluster but also help to develop more
cells upstream across W TX Panhandle over the next few hours,
likely to track northeast and trend toward later period possible
mergers. Total PWats at or just above 1.25" are filling in and
rainfall rates continue to increase in efficiency ranging from
1-1.5"/hr.=20=20

Given the placement of the expanding complex to the split in the
upper-level jet pattern; deep layer steering remains back-sheared
to the north and north-northwest and likely to continue to be slow
given the col in 500-1000mb thickness over the area. Forward
propagation will continue slowly eastward with combination of
strong inflow from the east, but also cold pool generation. As
such, residency of a few hours should allow for some localized
2-3" totals to manifest. As such, localized flash flooding
concerns will continue to remain through the early morning.=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5IuurpHag8RebIAYrUU8nV6Xfd1UM_XunzmHQmNAiEJWQH-ZVz3eKc0ZAA228OSGh7g4= bge6gwjtFwX1azMb6B8kjgI$ for graphic product...

ATTN...WFO...ABQ...AMA...LUB...MAF...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 35300296 34420154 33460106 32500121 31620182=20
31120236 29850354 29830467 30790482 31910477=20
32610430 33200413 34500414 35220393=20

=3D =3D =3D
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AWUS01 KWNH 261347
FFGMPD
TXZ000-261945-

Mesoscale Precipitation Discussion 0247
NWS Weather Prediction Center College Park MD
946 AM EDT Tue May 26 2026

Areas affected...West Texas

Concerning...Heavy rainfall...Flash flooding likely

Valid 261345Z - 261945Z

SUMMARY...A line of training thunderstorms across portions of west
Texas this morning contains cells capable of 2+ inches/hour
rainfall rates. Flash flooding is occurring resulting from these
storms.

DISCUSSION... An area of convection at the base of a highly
negatively tilted trough over New Mexico has been producing 2+
inch per hour rainfall rates across a portion of west Texas this
morning. These storms have been slow-moving, allowing for the
heavy rain rates to persist over the same areas for an extended
period. At the south end of the line, much faster moving storms
are pressing east just north of the Rio Grande in the Big Bend
region. CAMs guidance is suggesting that once the storms to the
south "catch up" longitudinally with the line just east of
Midland, the whole new line of storms will take on a faster
forward speed towards the east. This will reduce the flash
flooding threat a bit going forward, but rainfall rates with the
strongest cells will still pose a localized flash flooding risk
with 1-2 inches/hour still possible.

As the line progresses eastward towards San Angelo this afternoon,
with daytime heating, expect multiple individual slow-moving
thunderstorm cells capable of heavy rainfall rates to merge with
the line. Where these mergers occur, localized flash flooding will
be possible due to the extended period of time any heavy rain will
occur over those areas. Many of the river valleys tend to
efficiently convert heavy rainfall to significant river rises in
this area, worsening any potential flash flooding. Behind the line
of storms, cold pools and much more stable air will end the heavy
rain and flash flooding threat.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-FAKY9L2F2kFTpx9statJZTQMKWk-a_ZTHSTWz1lq79q5OD2t7FnxJAtssbWaccWawJw= BJ0KEBURtrIVXYSH9Ks0QTI$ for graphic product...

ATTN...WFO...EWX...LUB...MAF...SJT...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 34230074 33800026 33060002 32639985 32019952=20
31059940 29999978 29100049 29340108 29660143=20
29760198 29740237 29720272 29870326 30170336=20
30450321 30750296 31110275 31770249 32570201=20
34180164=20

=3D =3D =3D
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AWUS01 KWNH 261605
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-262100-

Mesoscale Precipitation Discussion 0248
NWS Weather Prediction Center College Park MD
1204 PM EDT Tue May 26 2026

Areas affected...Southern Alabama and the Western Florida
Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 261604Z - 262100Z

SUMMARY...Clusters of storms are developing along the Gulf Coast
in a pocket of maximized instability and atmospheric moisture
content. The convection could produce rainfall rates to 3 inches
per hour where training occurs. Flash flooding possible.

DISCUSSION...With diurnal heating now in full swing, scattered
strong thunderstorms have developed over the western tip of the
Florida Peninsula, now extending into far southern Alabama. These
storms have formed in an area of increased instability due to
lesser prior cloud cover, as well as in a corridor of maximized
atmospheric moisture. SPC Mesoanalysis shows PWATs to 2.2 inches
just off the coast of Pensacola, and over 2 inches where the
storms have formed. SBCAPE values are around 3,000 J/kg, so the
storms have more than enough moisture instability to continue
growing upscale into the afternoon hours.

CAMs guidance shows the storms are likely to increase in coverage,
taking advantage of the plentiful moisture and instability.
Despite recent heavy rains in the area, 1-hr FFGs remain over 2
inches for all of the highlighted area, and in some cases near the
coast, close to 3 inches. Given those still high thresholds, flash
flooding will generally be possible, confined to where the storms
line up in such a way as to maximize the duration of heavy
rainfall. Several urban areas could see those storms, in which
case the local thresholds required to realize flash flooding will
be lower.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8AP8n9DQBcxSaphOD6Cm_94edGMSPkg73FfwEoXwDXkip_d7Ao2vXWJa_vyK3VdCEKAk= eSTt-XmkzryxcTSEGZMqqfA$ for graphic product...

ATTN...WFO...BMX...LIX...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 32618641 32578606 31998571 31458548 30838535=20
30278549 30058558 30288603 30378660 30348716=20
30198750 30178832 30238868 30148918 30358927=20
30398927 30648930 31098900 31678871 32068818=20
32458755=20

=3D =3D =3D
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AWUS01 KWNH 262038
FFGMPD
TXZ000-270200-

Mesoscale Precipitation Discussion 0249
NWS Weather Prediction Center College Park MD
437 PM EDT Tue May 26 2026

Areas affected...central to south-central TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 262035Z - 270200Z

SUMMARY...A few widely scattered areas of flash flooding will be
possible across the Hill Country into south-central TX through
02Z. Hourly rainfall of 1 to 2 inches will be common but isolated
higher values of 2 to 3 inches will also be possible.

DISCUSSION...Regional radar imagery over west-central TX showed a
largely forward propagating broken axis of thunderstorms
stretching from the southern TX Panhandle to near Del Rio and
northern Coahuila. More discrete cellular development was located
ahead of this axis from the I-10 corridor across the Hill Country
and as far south as US-57, with a general movement toward the
northeast. The environment across this region of TX contained
1500-3000 J/kg MLCAPE with little to no inhibition, PWs of 1.5 to
1.8 inches and sufficient shear along and south of I-10 for
organized cells (via 20Z SPC mesoanalysis). Forcing in the mid to
upper levels was coming from a negatively tilted trough axis over
West TX and divergent and diffluent flow within the left-exit
region of a 100-120 kt subtropical jet over northern Mexico.

A mixture of supercell, multicell and ordinary cells are expected
given the environment with a range of speeds from the south to
west. Right-moving supercells should have the slowest movement
toward the east at ~10 to 20 kt. Some additional convective
development ahead of the forward propagating axis to the west is
anticipated through the remainder of the afternoon into the
evening within the unstable environment. Higher rainfall rates
will occur with areas of short-term training where line segments
within the western axis of thunderstorms matches the deeper layer
mean wind from the southwest allowing for 1 to 2+ inches of rain
in an hour. Additional potential for higher rates will come from
cell mergers and brief upstream development/training along and
ahead of this axis. The combination of factors above may result in
a few widely scattered areas of flash flooding, especially where
overlap of higher rates occurs with lower flash flood guidance of
the TX Hill Country to the I-35 corridor.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8KWeFV38JD7C_rWzAfPhhg8at7ud3cSFX5U0CWA_WPJ6-Pk_wMsoM6jkr_AAVscdeZHN= NYwSkwlQF5yQ5LkGagoJWMw$ for graphic product...

ATTN...WFO...CRP...EWX...FWD...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON 31499951 31349867 30849776 29989740 29199745=20
28409828 28049924 28010024 29010090 29510126=20
30170124 30710067 31390013=20

=3D =3D =3D
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AWUS01 KWNH 262251
FFGMPD
NCZ000-SCZ000-GAZ000-270445-

Mesoscale Precipitation Discussion 0250
NWS Weather Prediction Center College Park MD
650 PM EDT Tue May 26 2026

Areas affected...east-central GA into central/northern SC

Concerning...Heavy rainfall...Flash flooding possible

Valid 262249Z - 270445Z

SUMMARY...Training of heavy rain and flash flood potential will
increase from east-central GA into central/northern SC through the
early overnight hours. 1 to 2 inch per hour rates (or 1 to 2
inches in less than 1 hour) and 2 to 4+ inch totals will be
possible through 05Z.

DISCUSSION...GOES East visible imagery through 2230Z showed the
inland push of a sea breeze boundary extending from just south of
Columbia, SC into portions of southeastern GA. A few thunderstorms
were located along the boundary but there was generally a higher
coverage in SC compared to GA. Meanwhile, scattered thunderstorms
were located across the Piedmont of SC into GA with a general
movement toward the NNE, except in SC, where southeastward
advancing outflow was causing propagation toward the east. SPC
mesoanalysis data from 22Z showed 1000-2000 J/kg MLCAPE remained
along with high PW values of 1.8 to 2.2 inches from GA into SC,
containing estimated wet bulb zero heights of 12-14 kft.

Some degree of continued inland advancement is expected with the
sea breeze boundary containing scattered thunderstorms over the
next 1-3 hours. Meanwhile, RAP forecast guidance has been
suggesting 0-1 km flow becoming increasingly confluent along the
western edge of the sea breeze boundary as veered flow occurs over
the western half of GA. The combination of low level
convergence/confluence atop modest diffluece aloft is expected to
yield an increase in convection over portions of southeastern GA
over the next 1-3 hours with a general NNE movement of cells. The
alignment of cells with the deeper layer mean wind could support
some periods of short term training. Farther north into SC, The
eastward advancement of ongoing thunderstorms over Upstate SC,
meeting with advancing activity farther east, could allow for
mergers and brief training/high rain rates.

The environment is supportive of warm rain processes and efficient
rainfall production with potential for 1 to 2 inches of rain in
15-30 minutes. Due to 3 to 6+ inches of rain that has fallen over
a good portion of the region over the past 3 days, flash flood
guidance is lowered in a several locations with the potential for
isolated to widely scattered flash flooding possible through 05Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9y3eVJRYyNYfDoUWD-8_sx_obLFJMjW9Hbkv0xidNsj26HrBi0cO4OF8ZZVCtTRNxzCP= ZwQws_EK2rtEjYislsp_zGk$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...GSP...JAX...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 35188124 34938073 34538034 33938028 32918094=20
31168207 30758244 30818281 31178305 32288316=20
33558300 34518253 35168179=20

=3D =3D =3D
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AWUS01 KWNH 270215
FFGMPD
TXZ000-270630-

Mesoscale Precipitation Discussion 0251
NWS Weather Prediction Center College Park MD
1014 PM EDT Tue May 26 2026

Areas affected...central to south-central TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 270212Z - 270630Z

SUMMARY...An ongoing flash flood threat will linger across
portions of central TX over the next 3-4 hours. Meanwhile, a new
flash flood threat will evolve farther south from near the Rio
Grande into south-central TX after ~05Z. Peak hourly rainfall of 2
to 3 inches (locally higher) is expected.

DISCUSSION...Regional radar imagery at 0145Z showed a forward
propagating linear convective cluster arcing eastward from SPS to
ACT to SCI with a SW to NE orientation allowing for MRMS-derived
hourly rainfall of 1 to 3 inches from eastern Kerr to western Bell
counties. Farther south, a severe bowing linear segment was
identified over I-35, southwest of San Antonio.

As the southern end of a negatively tilted upper level trough axis
continues to advance eastward into central/south-central TX over
the next 6 hours, favorable ascent aided by the divergent and
diffluent left-exit region of the subtropical jet across northern
Mexico will maintain lift across central/southern TX.

=46rom roughly San Antonio and points northward, an additional 2 to
4 inches of rain will be possible as the NE to SW line of
thunderstorms continues to advance east, with hourly rainfall of 1
to 2+ inches. Locally higher hourly rainfall totals will be
possible where the northern end of the bowing segment SSW of San
Antonio meets with the line segment to the north, allowing for the
potential for 2 to 3+ inches of rain in an hour. However, the
flash flood threat is expected to gradually diminish through 06Z
for the northern (central TX) locations.

Farther south however, there is growing concern for flash flooding
to evolve across the Rio Grande Valley into portions of
south-central TX later in the night as upstream/developing
convection intensifies and moves east across Coahuila, potentially
merging with new convective development along the remnant outflow
boundary related to the bowing segment. This may occur as low
level southerly flow interacts with the boundary where sizable
MLCAPE will remain (2000+ J/kg). Should this scenario unfold, with
specific timing remaining uncertain, flash flooding will be
possible from Maverick to Webb counties and points east.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4cFWqlYHF_-fASHLvqtlsWdrSANYog6IRnbG_KE6yNY96rAevF7INQ_x25VkvWH9pa-c= yv3gSvjyS-DuQbamtbrQW9Y$ for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...

ATTN...RFC...FWR...NWC...

LAT...LON 31899650 31759613 31449609 31109617 29749641=20
28819701 27719803 27279906 27609986 28100023=20
28550043 28709994 28939942 29629920 30159879=20
31119792 31689740 31819710=20

=3D =3D =3D
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AWUS01 KWNH 270414
FFGMPD
SCZ000-GAZ000-270900-

Mesoscale Precipitation Discussion 0252
NWS Weather Prediction Center College Park MD
1213 AM EDT Wed May 27 2026

Areas affected...Eastern Georgia...Central South Carolina...

Concerning...Heavy rainfall...Flash flooding possible

Valid 270415Z - 270900Z

SUMMARY...A few more hours of potential repeating high efficiency
thunderstorms across same corridor/wetter upper-soil conditions.=20
Localized flash flooding potential remains possible overnight.

DISCUSSION...GOES-E WV suite denotes very little
evolution/transition of the subtropical high location with just a
slight flattening of the northeast side of the ridging across NC/E
SC. As such, the next in a sequence of jet streak enhancements is
sliding along this section through the Cumberland Plateau=20
providing anticyclonic divergence along the western periphery of
the area of concern. The MPD remains aligned with the confluent
surface to mid-level warm conveyor belt, which continues to
receive confluent upstream from the western Atlantic feeder
through northern FL into southern GA resulting in flux convergence
and total PWat values of 2-2.25" still fairly anchored across the
same corridor from the Okefenokee Swamp to the Augusta, GA region
before deflecting across the Piedmont/central Fall-line of SC.=20
This slight cyclonic curvature further supports convergence and
increased overlap of the remaining instability axis to the east
across the I-95 corridor in GA and through S SC. While overall
low-level flow is slightly weaker at 10-20kts, there remains
sufficient deep layer convergence with 750-1000 J/kg of
narrow-skinny CAPE for a few more hours of scattered thunderstorm
activity.

Given the deep layer moisture and warm cloud depths, rainfall
efficiency should remain high at 2"/hr. Slow north to
northeastward propagation along the same corridor as the last few
days will allow for intense rainfall to fall upon increasingly
deeply saturated grounds with relative soil moisture values over
70% dotted along the axis. Given the rates and limited capacity
in the upper-soils, there should be increased run-off perhaps
resulting in similar widely scattered but focused incidents of
flash flooding as seen over the past few hours.

While the deep layer flow suggests areas along the Fall-line of
central SC and northwest where FFG values are most compromised
should remain far enough northwest given current trends. However,
a small deviation due to storm scale interactions still may result
in this area remaining at risk for the earlier portions of the
overnight period and have been included in the MPD area of concern.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!43sc9HScZLRX0coppH4K0Jfsbc6vv3pU569B2q_PjLtiQLmw0MaaiJ-U_LOF-yNRM-4A= smfnE3Wg4zJMMdDnrgGYt18$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...GSP...

ATTN...RFC...ALR...NWC...

LAT...LON 34818165 34728081 34258026 33808018 33418034=20
33108063 32438138 32168162 31928183 32138275=20
32888262 33628256 34368236=20

=3D =3D =3D
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AWUS01 KWNH 270530
FFGMPD
TXZ000-271100-

Mesoscale Precipitation Discussion 0253
NWS Weather Prediction Center College Park MD
129 AM EDT Wed May 27 2026

Areas affected...Eastern & Southeast Texas...

Concerning...Heavy rainfall...Flash flooding possible

Valid 270530Z - 271100Z

SUMMARY...Urban flash flooding risk as squall line weakens and
stalls along the central TX coast, with quick burst of sub-hourly
totals of 1.25-1.75", resulting in localized 2-3" and possible
flash flooding overnight.

DISCUSSION...
Regional RADAR and 05z surface analysis shows strong, mature,
progressive squall line emerging from the I-35 corridor moving
into the Central Texas Coastal Plain rapidly approaching the
College Station to Houston urban areas and moving out of MPD 251=20
A pool of conditionally unstable air awaits it along the upper to
central TX Gulf coast with low to mid-70s Tds (with some upper
70s directly on the coast) and MLCAPE of 2000-3000 J/kg from a
preceding surface trof from KCLL to KJAS into central LA and
southward. Strong inflow and latent heat release aloft should
continue to maintain that forward progress, but the shear
magnitude of moisture fluxed into the leading edge will support
very intense instantaneous rain-rates with 15-30 minute 1.25-1.75"
totals expected given current observational trends and recent HRRR
forecast trends. For the most part, the totals will remain at the
edge/just below all naturally higher FFG values (1-6hrs) but urban
and traditionally prone, poorly draining locations are probable to
be overwhelmed in short-term. The question will be the overall
volume and given the breadth of the squall line, neighboring
upper-reaches of small watersheds may compound quickly for
localized rapid inundation flash flooding.

North of the trough axis, deep layer steering shifts to support
back-shearing from southeast to northwest into the deepening
outflow channel, cold pool and surface meso-highs are much weaker
and left-bookend/cyclonic eddy may allow for slightly reduced
rates/downdraft intensity to linger/greater residency to approach
similar localized 2-3" totals. This still may not reach the
higher FFG values in the area, but there remains a low-end risk
for flash flooding here as well, especially near urban locales.=20=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9XGS5W5EHcaDcVlgv6ljeUn_Y8gGB-rnq1ClTqqtUklx4OJ7UUCCgY9-0jXozHJ2yhzg= fqFyVeo39SXpn-qU1dG3cxQ$ for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SHV...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON 33189613 33159523 32549462 31249394 30679380=20
29959380 29159478 28539581 27989692 28329757=20
28909760 29819715 30449675 31349606 32099612=20
32829644=20

=3D =3D =3D
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AWUS01 KWNH 270611
FFGMPD
TXZ000-271200-

Mesoscale Precipitation Discussion 0254
NWS Weather Prediction Center College Park MD
210 AM EDT Wed May 27 2026

Areas affected...South Texas...

Concerning...Heavy rainfall...Flash flooding likely

Valid 270610Z - 271200Z

SUMMARY...Flattening squall line with upstream deepening wave,
likely to result in expanding convective environment with ample training/repeating opportunities and likely result in 3-5" totals

DISCUSSION...Regional RADAR shows mature progressive squall line
crossing along I-10 through the central Texas Coastal Plain with
the anti-cyclonic rotor of the squall resulting in a flattening
west to east outflow boundary across south-central to southern
Texas. A strong, broad super-cell anchors the base of the line
with overshooting tops colder than -80C. Surface and VWP show
southeasterly veering to southerly at 15-20kts and 35-40kts,
respectively intersecting this boundary, leading to strong
isentropic ascent. The advected air remains very unstable with
MLCAPEs of 3500-4000 J/kg with mid to upper 70s Tds; resulting in
strong to extreme moisture flux convergence 20+ kg/m/s.

GOES-E WV suite notes and upstream speed max in the sub-tropical
jet is dipping the orientation ever so slightly to support
diffluence aloft, which is also aiding development of an embedded
shortwave feature near 27.5N102W, leading to a new convective
cluster over the Sierra Madre, still fairly displaced from the
deeper surface to 850mb moisture. However, CIRA LPW does note
that downstream of the wave, cross Mexican 850-700 and 700-500
moisture connection intersects over the Lower Rio Grande Valley to
support 2-2.25" total PWats. The combination of the approaching
upper-level forcing with the isentropical ascent/convergence is
likely to fill in the line between the upstream cluster and the
tail of the squall. Strength of updrafts and flux convergence
will support very intense sub-hourly burst, but hourly
rates/totals of 2-3" are probable along the axis due to deep layer
steering supporting repeating/training environment. There remains
some uncertainty to the vigor of the cold pool generation and
therefore the propagation vectors are wavering between due east
and southeast within the Hi-Res CAM guidance suite. No deviation
may result in the most extreme totals from Webb to San Patricio
county with localized spots in excess of 6-7" by 12z; while more
deviation to the southeast will broaden the overall heavy rainfall
coverage to 3-4" areal expectations.=20=20

While FFG values are naturally high, the shear moisture flux and
rates with any increased residency, which looks very likely, will
result in flash flooding conditions; if duration would to align
with urban locations, such as Corpus Christi; inundation flooding
could be considerable.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8O3XZqK8S-30Y47xAsJel_YCB0ORWKjuTdXMYWfd5selvNjk3eIZe_hUkWhezQJ550KM= pa2ekzjYHR9GcOuMyDMn5Qw$ for graphic product...

ATTN...WFO...BRO...CRP...EWX...

ATTN...RFC...FWR...NWC...

LAT...LON 29029723 28579667 28179654 27659707 26889741=20
26759840 26999955 28430046 28889905=20

=3D =3D =3D
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AWUS01 KWNH 270657
FFGMPD
PAZ000-MDZ000-WVZ000-OHZ000-INZ000-271245-

Mesoscale Precipitation Discussion 0255
NWS Weather Prediction Center College Park MD
256 AM EDT Wed May 27 2026

Areas affected...Eastern IND...Central OH...Southeast PA...Western
MD... Northern WV...

Concerning...Heavy rainfall...Flash flooding possible

Valid 270700Z - 271245Z

SUMMARY...Scattered warm-advection showers will have high rainfall
efficiency with rates up to 1-1.5"/hr will eventually stall and
align favorably for repeating along the mid-level front. Streaks
of 1-2" over recently saturated soils pose widely scatted
incidents of possible flash flooding.

DISCUSSION...GOES-E WV suite depict the elongating/shearing older
closed low near St. Louis Missouri with a deep laminar elongated, deformation/shear axis across central IL/IND/OH and PA. South of
which, broad south to south-southwesterly 15-20kt low-level jet is
lifting the surface front more in line with the aforementioned
axis. Deep layer moisture remains pooled along the steepening
frontal zone with values of 1.5-1.75" (slightly higher further
east). Further west, a bit of drier air aloft and therefore
slightly steepened lapse rates is support some 500-1000 J/kg of
MUCAPE, though this becomes 250-500 J/kg further east through the
central Appalachians. As such, solid moisture flux convergence
along the vertically steepening isentropic boundary is starting to
break out a few narrow currently scattered showers from central IL
through eastern OH. WV suite also denotes core of upper-level jet
streak over central OH before turning eastward over PA/NY,
providing some modest divergence aloft, again slightly east.

All elements considered the updrafts will support efficient
rainfall production given the moist environment but due to the
likely narrow updrafts due to weak instability, rates of .75-1"/hr
will be more common, though ideal storm-scale interactions may
allow for up to 1.5" locally and for short time periods. Ascent
will continue through the late overnight period/early morning with
increasing convective cells along the boundary. Deep layer
steering quickly veers along the shear axis to support west to
east propagation and potential for these showers to repeat.

As such, localized streaks of 1-2" are possible though the morning
with increasing potential from central OH to the spine of the
Appalachians. Recent prolonged moderate to heavy rainfall has
soaked the upper-soil environment particularly over E OH into the
central Appalachians, where hourly FFG value are barely over 1"
and 3hr values are mostly less than 1.5". Further west into
central IL/IND, FFG values rise and are likely to be just out of
reach with only exception for a very isolated stationary cell or
two. As such, localized incidents of flash flooding will be
considered possible from Eastern IND into SE PA/W MD/E WV.=20

Note: There are some hints of prolonged training events within the
Hi-Res CAM suite with higher localized totals of 2.5"+. While
confidence is not high, these unidirectional flow regimes with
trapped deep layer moisture, vorticity and prolonged training
potential can be particularly dangerous especially in the complex
terrain of E OH, N WV and SE PA/W MD.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6z5JaBq1DiZS0Bi0r2lQJtOQQgR7npXAVFCKxVzfESqNvEuIl93hMzYYPQHF_f7DXHt7= O_Z33TWe2grjJU-ruADxGGo$ for graphic product...

ATTN...WFO...CLE...CTP...ILN...IND...LWX...PBZ...RLX...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON 40378148 40307964 40047857 39757831 39227854=20
38667926 38808013 39188204 39308360 39238533=20
39658569 39998566 40318460=20

=3D =3D =3D
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AWUS01 KWNH 271200
FFGMPD
TXZ000-271459-

Mesoscale Precipitation Discussion 0256
NWS Weather Prediction Center College Park MD
759 AM EDT Wed May 27 2026

Areas affected...portions of Deep South Texas

Concerning...Heavy rainfall...Flash flooding likely

Valid 271159Z - 271459Z

Summary...Flash flood potential continues as a convective complex
spreads 1-2.5 inch/hr rain rates across the region this morning.

Discussion...An intense convective complex continues to migrate
across Deep South Texas this morning. The northern portion of the
complex (extending from near Karnes City to near Corpus Christi)
was fairly progressive, with only isolated mergers noted that were
boosting local rain rates above 2 inches/hr. FFGs are low in
these areas from prior rainfall, and FFG exceedences were noted.=20
Flash flood potential will likely exist for the next couple hours
as this part of the complex reaches the middle Texas coast through
14Z.

Of somewhat greater concern is focused, training convection on the
southwestern side of this complex. Convection in that area was
oriented more parallel to steering flow aloft while remaining
closer to steep mid-level lapse rates aloft, supporting
backbuilding. A mid-level wave was evident per objective analyses
along the Rio Grande Valley near Cotulla. That wave should
continue to make slow northeastward progress through south Texas
this morning, prompting continued, upstream updraft development.=20
The temporal extent of this backbuilding is a bit uncertain -
though it appears that at least two more hours of backbuilding
convection (and rates approaching 3 inches/hr) are possible.=20
Flash flooding is expected - especially if these downpours can
begin to affect more populated areas.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9H_mZt6YGd09u9KltefruWuPDwDOaiU6U6P2P_g9mMBVbabLsm2uLMThFmAbmcoRapd9= NeHIuskPe0ji6_1Ci_ZQPiY$ for graphic product...

ATTN...WFO...BRO...CRP...EWX...HGX...

ATTN...RFC...FWR...NWC...

LAT...LON 30179711 29969549 28899531 27739645 26719708=20
26109729 26199856 26939979 27940007 28519909=20
28739834 29989832=20

=3D =3D =3D
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AWUS01 KWNH 271255
FFGMPD
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-INZ000-271853-

Mesoscale Precipitation Discussion 0257
NWS Weather Prediction Center College Park MD
854 AM EDT Wed May 27 2026

Areas affected...portions of Indiana, Ohio, West Virginia, western
Maryland, and southwestern Pennsylvania

Concerning...Heavy rainfall...Flash flooding likely

Valid 271253Z - 271853Z

Summary...Flash flood potential will continue through at least
18Z/2p eastern today.

Discussion...Scattered convection continues to remain focused
along and just north of a warm frontal zone located from central
Indiana eastward though northern West Virginia. Along and south of
this boundary, near 70F dewpoints were supporting areas of
500-1000 J/kg MUCAPE along with 1.6 inch PW values. These
thermodynamics were supporting briefly heavy rainfall due to
localized training despite appreciable storm motions (around 30
knots or so). Spots of 1 inch/hr rain rates were noted over West
Virginia and in western Ohio, which were approaching or even
exceeding FFG thresholds on a localized basis (<0.75/hr in spots).

The overall regime should continue through at least 18Z/2p today
and likely beyond. The warm frontal zone will move very little
today while weak mid-level waves and subtle convergence along the
front support redevelopment of convection. Occasional training
bands will readily exceed FFG thresholds on an isolated to
scattered basis, and an appreciable coverage/number of flash flood
instances are expected given the regime and sensitivity of ground
conditions across the region. Areas of rainfall totals reaching 3
inches are possible through 18Z, especially with convective
coverage expected to increase due to surface
heating/destabilization expected through the morning.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!46EgCW9vjFnu1lOif4X0tTIBXtiE_fWIG8EzQXxCnmota-0dXNJ3tJwftZJP9AdqA6v_= -uHRqEV3Of_z5NtFySMJwmY$ for graphic product...

ATTN...WFO...CLE...CTP...ILN...IND...IWX...LWX...PBZ...RLX...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON 40998239 40828009 40377813 40137789 39497770=20
39157782 38747857 38467979 38618174 39288398=20
39508616 40178658 40838612 40978465=20

=3D =3D =3D
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AWUS01 KWNH 271322
FFGMPD
DEZ000-MDZ000-VAZ000-DCZ000-271519-

Mesoscale Precipitation Discussion 0258
NWS Weather Prediction Center College Park MD
920 AM EDT Wed May 27 2026

Areas affected...Maryland, District of Columbia

Concerning...Heavy rainfall...Flash flooding possible

Valid 271319Z - 271519Z

Summary...Isolated flash flood potential will exist as a cluster
of storms over western Maryland moves through the region this
morning.

Discussion...A persistent cluster of thunderstorms was noted via
radar mosaic imagery near Frederick. These cells have shown
modest signs of intensification in the last few minutes. They are
being supported by weak mid-level waves moving through zonal flow
over northern VA and near 70F dewpoints that were fostering 1.75-2
inch PW values and ~1000 J/kg MUCAPE. Despite current rain rates
of 0.5-0.75 inch/hr, moisture values increase with downstream
extent toward the Chesapeake Bay. Though appreciable steering
flow was supporting fairly quick movement of individual cells
(around 35-40 knots), increasing downstream moisture profiles and
urban ground surfaces/lower FFGs nearer to I-95 (0.75 in/hr) may
support isolated instances of flash flooding this morning. This
potential should be brief (perhaps extending through 15Z/11a).=20
More upstream convection is possible later today and will be
monitored for any flash flood potential beyond 15Z.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5igO96g-vGZ-IIMMg39nVl5zsxBvbZHOry29pAv0nGBaIt3RunBWy5jNiTncz1mP9jIb= 49E2ugkjZCi8kpY0Hxv1RQo$ for graphic product...

ATTN...WFO...LWX...PHI...

ATTN...RFC...RHA...NWC...

LAT...LON 39727661 39527578 38907572 38667657 39187757=20
39657737=20

=3D =3D =3D
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AWUS01 KWNH 271444
FFGMPD
TXZ000-OKZ000-271842-

Mesoscale Precipitation Discussion 0259
NWS Weather Prediction Center College Park MD
1043 AM EDT Wed May 27 2026

Areas affected...portions of north Texas, including Dallas/Fort
Worth Metro

Concerning...Heavy rainfall...Flash flooding possible

Valid 271442Z - 271842Z

Summary...A very slow-moving band of convection has formed over
eastern Dallas metro while producing rainfall rates approaching 3
inches/hr. Flash flood is likely with this activity over the next
2-4 hours.

Discussion...A focused band of convection near eastern Dallas
metro has materialized over the past hour or so. The convection
was focused along enhanced low-level convergence on the western
edge of 20-30 kt 850mb flow in northeast Texas. A weak surface
low was also noted in the general vicinity of the convection as
well. The low-level convergence was likely operating in tandem
with weak forcing from a mid-level wave over the area to force
deep ascent of an abundantly moist (1.8 inch PW) airmass with
sufficient conditional instability (~1000 J/kg MUCAPE) for strong
updrafts. Given the heavy rainfall rates and higher-end MRMS
Flash responses near Rockwall, it is likely that flash flooding is
imminent beneath this band if not already occurring.

The overall duration of this flash flood scenario is in question
and will likely be tied to the persistence of enhanced, easterly
low-level flow into the axis of convection. RAP/mesoanalyses
suggest that this axis will weaken eventually, but may take a few
hours to do so. A slow westward/northward drift will likely occur
as long as convection persists, and with intense local rainfall,
areas of 5+ inch rainfall totals cannot be ruled out through
18-19Z (approx 2p central). Flash flooding is likely, and with
nearby urban population centers at risk, significant impacts
cannot be ruled out.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_bBFtQ-mamIxqGAtMhmZvdPZ824oI-Sf1fyb_zB5mMiJurwKYj0voKYbA0bPEA3VzIyq= xjbAgihYQ9foyCc_TgunhQs$ for graphic product...

ATTN...WFO...FWD...OUN...SHV...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 33839674 33729587 33129552 32229564 32109661=20
32849731 33749723=20

=3D =3D =3D
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AWUS01 KWNH 271659
FFGMPD
ARZ000-TXZ000-OKZ000-272258-

Mesoscale Precipitation Discussion 0260
NWS Weather Prediction Center College Park MD
1258 PM EDT Wed May 27 2026

Areas affected...portions of southern, central, eastern Oklahoma,
far north Texas, and far western Arkansas

Concerning...Heavy rainfall...Flash flooding possible

Valid 271658Z - 272258Z

Summary...A convective complex over north-central Texas is
drifting northward and should spread areas of 1-2 inch/hr rain
rates into the discussion area over the next 2-4 hours. Flash
flooding is possible with this activity.

Discussion...A focused band of convection near east Dallas metro
has gained mesoscale organization over the past hour while
drifting northward and producing 6-8 inches of rainfall (estimated
per MRMS/radar). That convection continues to remain organized,
but has exhibited some weakening/lessening of rain rates over the
past 30 minutes. Easterly low-level inflow and strong confluence
near the convection continues to pose a heavy rain risk in the
near term - especially in/near Sherman, McKinney, and Rockwall.

The downstream airmass feeding convection continues to be plenty
moist (1.5+ inch PW) and unstable (2000 J/kg MUCAPE), with plenty
of sunshine/destabilization noted across eastern Oklahoma and
Arkansas. The north Texas complex was already beginning to prompt
heavier rain rates in far southern Oklahoma near Durant, and
additional convection is expected over time across the entire
discussion area given the combination of destabilization/ascent
and weak inhibition.

FFG thresholds are higher with northward extent from the Red River
into southern/central Oklahoma (around 2 inch/hr). Flash flooding
will remain possible, but will likely be tied to areas of training
and cell mergers that can boost local rainfall totals. This flash
flood threat will persist through at least 22Z/5p central.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7sT6f42c4FNkoyxiNGcy0JWPUWfetRgT33hrOll18s3b1UMrfG--Y3rQu4CdMPRZoPty= YygrexNHvG-j56b1fWs_Kwk$ for graphic product...

ATTN...WFO...FWD...LZK...OUN...SHV...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 36439509 35749396 34129398 33699460 33569555=20
33349645 33819735 35599735 36349658=20

=3D =3D =3D
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AWUS01 KWNH 271950
FFGMPD
MDZ000-VAZ000-WVZ000-OHZ000-KYZ000-INZ000-280130-

Mesoscale Precipitation Discussion 0261
NWS Weather Prediction Center College Park MD
349 PM EDT Wed May 27 2026

Areas affected...OH Valley into Central Appalachians.

Concerning...Heavy rainfall...Flash flooding likely

Valid 271947Z - 280130Z

Summary...A few areas of flash flooding will be possible across
the OH Valley into the central Appalachians over the next 3-5
hours. Rainfall rates of 1-2 in/hr area expected and shorter fused
rates of over 0.5 inches in 15 minutes will also be possible.

Discussion...Visible satellite imagery and surface observations at
1930Z showed a southward sinking outflow boundary that extended
from the southwestern corner of southwestern PA into southern OH
and into south-central IN, co-located with scattered showers and
thunderstorms. Additional thunderstorm activity was noted south of
the outflow boundary from eastern KY into central WV, out ahead of
a pair of vorticity maxima observed on water vapor imagery. A
larger scale vorticity max/shortwave was observed across IL/IN,
with eastward motion, helping support lift across the region.
MRMS-derived hourly rainfall was largely below 1 inch for a
majority of the the region, with the exception of south-central IN
where training was supporting hourly rainfall of 1 to 2 inches but
also 15-minute rates of 0.5 to 1.0 inches.

With ample moisture/instability remaining in place via 19Z SPC
mesoanalysis data (500 to 1500+ J/kg MLCAPE and PWs of 1.5 to 1.7
inches), and continued forcing from ascent along/ahead of the
outflow and ahead of the upstream shortwave/vorticity maxima,
scattered thunderstorms will continue across the OH Valley into
the central Appalachians through the early evening. Expectations
are for individual cell movement toward the east at an average
speed of 10-25 kt but with system evolution toward the south with
time. Brief training will briefly enhance rain rates with 1 to 2
inches of rain in an hour or less, likely supporting a few areas
of flash flooding across the OH Valley into the central
Appalachians where flash flood guidance values are mostly ~1 inch
per hour.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_b-um9cBG32hinS9h0nsHCX6JVXaJXHQKVf5ihAOeJa5-677MN_JCdIxF56NzjE9uG7E= Nbpr-rm5oitn8zxWkhxApvk$ for graphic product...

ATTN...WFO...ILN...IND...JKL...LMK...LWX...PBZ...RLX...RNK...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON 39738605 39598500 39108341 39298184 39688014=20
39027906 38297916 37558034 37558172 37778368=20
37838433 38368599 39158629=20

=3D =3D =3D
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AWUS01 KWNH 272043
FFGMPD
VAZ000-NCZ000-280230-

Mesoscale Precipitation Discussion 0262
NWS Weather Prediction Center College Park MD
442 PM EDT Wed May 27 2026

Areas affected...south-central to southeastern VA into far
northern NC

Concerning...Heavy rainfall...Flash flooding possible

Valid 272040Z - 280230Z

SUMMARY...Flash flooding will be possible over south-central to
southeastern VA into far northern NC through ~02Z. Rain rates of
1-2 in/hr and total rainfall of 1 to 3 inches are expected, with
possible overlap with locations that have picked up heavy rain
over the past couple of days.

DISCUSSION...GOES-E visible satellite imagery at 2030Z showed a
southward sinking outflow boundary from the southern DelMarVa
Peninsula into central VA and a second outflow boundary from
south-central VA into northwestern NC. The environment south of
the northern outflow was estimated to contain 1000-2000 J/kg
MLCAPE and PWs near 2 inches per 20Z SPC mesoanalysis data. As the
northern outflow boundary continues to advance toward the south
into the evening, additional convective development is expected
along/ahead of the boundary with cells containing a mean west to
east motion at 20-30 kt. Due to the similarly oriented low to
mid-level flow and the boundary orientation, some brief training
of heavy rain will be possible over the next 3-6 hours, with
clearing occurring from north to south over time.

Portions of southern/southeastern VA have received 3 to 6+ inches
of rain over the past 48 hours and have limited capacity for
additional infiltration of water. Therefore, hourly rainfall of 1
to 2 inches and the potential for isolated totals near 3 inches
could support areas of flash flooding through 02Z to 03Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!64TL9NajwaPmIhCwxLrlTX0gRhZ9C9--NwtEw9gRsuGJf2vclY7WDfZHD47F1XLCAgTF= 1lTxXfMamkO_dzvK5qGIqIM$ for graphic product...

ATTN...WFO...AKQ...LWX...RAH...RNK...

ATTN...RFC...ALR...RHA...TIR...NWC...

LAT...LON 37907655 37537567 37037545 36507571 36417673=20
36437775 36437906 36528003 37148017 37757815=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 280524
FFGMPD
TXZ000-OKZ000-KSZ000-COZ000-281123-

Mesoscale Precipitation Discussion 0263
NWS Weather Prediction Center College Park MD
123 AM EDT Thu May 28 2026

Areas affected...Portions of the Central and Southern High Plains

Concerning...Heavy rainfall...Flash flooding possible

Valid 280523Z - 281123Z

Summary...An increasing threat for localized flash flooding will
occur over portions of western Kansas into the adjacent Oklahoma
and Texas Panhandles as rainfall rates approach 2 inches per hour
at times.=20

Discussion...Broad upper level troughing with multiple smaller
mid-level perturbations pivoting around the general circulation
are causing a period of unsettled weather over the Central and
Southern Plains this evening. At the surface, a defined surface
trough axis is positioned over the western High Plains of Kansas
down through the Oklahoma and Texas Panhandles with an area low
pressure centered near Amarillo, Texas. Within the bounds of the
surface trough, deep moisture and prominent instability maximum is
co-located within the surface trough axis' and under the main area
of circulation positioned over the New Mexico/Colorado/Kansas
border. The alignment of the surface trough and primary upper
trough correlate to a more formidable area of forcing which is
well-documented in the latest deep moisture convergence pattern
from the latest mesoanalysis.

KDDC this evening experienced PWAT anomalies approaching the
95-99th percentile of climatological means for this time of year,
a testament to the depth and magnitude of sufficient deep layer
moisture availability. MUCAPE between 500-1000 J/kg will be
positioned across the area of interest providing sufficient
buoyancy for updraft development and initiating stronger
convective cores capable of heavy rainfall production. A few cells
are already occurring in the region with pockets of 1-2"/hr rates
and some intra-hour pulses reaching near 3"/hr at times as cells
mature. Deterministic outputs from the latest HRRR and RRFS
indicate some localized amounts between 2-4" over the next 6 hours
as the axis of convergence within the surface trough placement
begins to levy a more enhanced convective footprint over the
course of the early morning hours, perhaps lingering through most
of the morning if some of the CAMs are correct.

The likelihood of flash flooding remains in the modest category
due to the antecedent soil moisture conditions over the area as a
prolonged drier pattern has firmly driven FFG's to a less
favorable scenario for flash flooding compared to normal. As a
result, there is a flash flood risk possible over the western High
Plains between Kansas, Oklahoma, far southeast Colorado, and the
northern Texas Panhandle.

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_--zGD1Hhgh1tmk6NVsMcJGiV3nLu5WZawmCS6KtDhgO7-1Tpqc3QGny0D0JHgyBDDt-= ChkxUSSk1N4pVR3t6WAlYVU$ for graphic product...

ATTN...WFO...AMA...DDC...GLD...OUN...PUB...

ATTN...RFC...TUA...NWC...

LAT...LON 38520115 38320041 37489993 36309960 35759966=20
35400025 35590117 36120209 36580235 37100235=20
37780237 38320211=20

=3D =3D =3D
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AWUS01 KWNH 281047
FFGMPD
FLZ000-281446-

Mesoscale Precipitation Discussion 0264
NWS Weather Prediction Center College Park MD
647 AM EDT Thu May 28 2026

Areas affected...urban southeastern Florida

Concerning...Heavy rainfall...Flash flooding possible

Valid 281046Z - 281446Z

Summary...Slow-moving downpours could cause urbanized flash flood
concerns this morning.

Discussion...A small cluster of thunderstorms was located near
Homestead. These storms were located along a subtle confluence
zone parallel to the southeastern Florida coast, which was
supporting strong updrafts amid minimal convective inhibition,
abundant moisture (1.8 inch PW values), and ~1000 J/kg MLCAPE.=20
Weak southerly steering flow was noted per objective analyses,
which should aid in slow northward migration of ongoing cells
through Miami/Ft. Lauderdale Metropolitan. Additionally, spots of
1-2 inch/hr rain rates were noted/estimated per MRMS, and should
these cells persist in intensity while drifting northward through
Miami, urban flash flood potential will increase. Models/CAMs
suggest that this isolated potential will persist for at least a
few hours this morning (through 14Z/10a eastern).

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8tsKz4nRfzLIgN7vvD_l55yLjrcwJ0HeTetn5-E3Aoyj53yUnaLrA56adgna9fI5GNnb= ITJDw9omCPb5QRG-HnoAV5M$ for graphic product...

ATTN...WFO...KEY...MFL...

ATTN...RFC...ALR...NWC...

LAT...LON 26818034 26817986 25328020 25348062 26288055=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 281616
FFGMPD
ALZ000-MSZ000-LAZ000-282214-

Mesoscale Precipitation Discussion 0265
NWS Weather Prediction Center College Park MD
1215 PM EDT Thu May 28 2026

Areas affected...southern Mississippi, southeastern Louisiana, far
southwest Alabama

Concerning...Heavy rainfall...Flash flooding likely

Valid 281614Z - 282214Z

Summary...A cluster of thunderstorms producing heavy rain rates is
evolving slowly primarily across southern Mississippi. Flash
flooding is likely on an isolated to scattered basis through at
least 19Z.

Discussion...Persistent warm advection has enabled scattered to
numerous thunderstorm activity in the general vicinity of
Hammond, Picayune, and Wiggins over the past 1-2 hours or so. The
storms are focused on the northern edge of enhanced 850mb flow
over the north-central Gulf (20-30 knots per RAP/SPC Mesoanalysis)
while also experiencing the glancing influence of upstream
mid-level waves providing ascent. Abundant moisture (2+ inch PW
values) and surface-based instability (exceeding 2000 J/kg) will
continue to support repeating thunderstorm activity within the
warm advection regime in place.

Models/CAMs support repeating thunderstorm activity from
southeastern Louisiana into southern Mississippi for a few more
hours, with hourly rain rates exceeding 2 inches per hour where repeating/training is most pronounced. These rates are likely to
exceed FFG over time and prompt flash flooding. Through 19-20Z,
models suggest that low-level flow/convergence will slacken some
and cause thunderstorm activity to 1) eventually shift to the
northeast of its current axis and 2) exhibit lesser coverage over
all. Some models remove thunderstorm potential entirely, but this
scenario is doubtful as persistent mid/upper troughing to the west
will provide lift/ascent for at least isolated thunderstorm
activity to persist after 20Z through peak heating. Despite high
FFGs across parts of southern Mississippi, high rain rates will
likely result in at least isolated instances of flash flooding
especially if rain can occur over more urban/sensitive interfaces.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-fvkGdfh2avWXaazlAGXCuI23fP4DkqifkF5JwmjFWOkDzBk9DzZQerSzyPfHBbDRTTE= 8cIGTkf1E0LecWwhhPoF6uQ$ for graphic product...

ATTN...WFO...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 32158946 32098858 31788813 30708810 30108843=20
29328918 29259045 30099053 31319053 31739041=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 281635
FFGMPD
MSZ000-MOZ000-ARZ000-OKZ000-KSZ000-282234-

Mesoscale Precipitation Discussion 0266
NWS Weather Prediction Center College Park MD
1234 PM EDT Thu May 28 2026

Areas affected...portions of Arkansas, southern Missouri, and far
southeast Kansas

Concerning...Heavy rainfall...Flash flooding likely

Valid 281634Z - 282234Z

Summary...Scattered thunderstorms were beginning to increase in
coverage and intensity especially across north-central Arkansas.=20
Slow movement and efficient rainfall activity will result in a few
areas of flash flooding through 22Z/5p central.

Discussion...Storms are increasing in coverage and intensity along
a general axis extending from near Flippin/Harrison south to near
Camden, AR over the last hour. The storms are being forced by 1)
ascent associated with a mid-level trough centered over Oklahoma
and 2) differential heating through that aforementioned axis
across central/north-central Arkansas. Abundant surface heating
east of the axis has allowed for 2000 J/kg MLCAPE to develop amid
an uncapped airmass, supporting deep convection. 2.1 inch PW
values are also supporting efficient rain rates within the
convection, while weak south-southeasterly steering flow aloft has
enabled slow storm motions and localized training. Rain rates
approaching 2 inches/hr have already been estimated in parts of
north-central Arkansas, which isn't surprising given the regime in
place to support heavy rain.

The ongoing scenario will evolve slowly today, with convection
continuing to expand northward and westward across the discussion
area today. Additional convective development across northeastern
Arkansas also appears likely. Areas of 3-4 inch rainfall totals
are expected, which will likely overwhelm low-lying/sensitive
areas and prompt flash flooding on and isolated to scattered
basis. This risk will likely persist through 22Z/5p central and
beyond, with convective coverage driven/modulated by the degree of heating/instability in the upstream airmass across the eastern
half of the discussion area.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8YIaDTTQNAXznO16YGvzw6lxt-8Y78isY3_puggJvnAgsTPd-2AUUKPZVym_p-XKJj8F= u_-t9EyCwgdR6bFTpUDOfro$ for graphic product...

ATTN...WFO...EAX...ICT...JAN...LSX...LZK...MEG...PAH...SGF... SHV...TOP...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 38759486 38329259 37449070 35879018 33759115=20
33119204 33489375 35429434 36949479 38009547=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 281705
FFGMPD
MSZ000-LAZ000-ARZ000-282104-

Mesoscale Precipitation Discussion 0267
NWS Weather Prediction Center College Park MD
104 PM EDT Thu May 28 2026

Areas affected...portions of eastern/northeastern Louisiana,
western Mississippi, and far southeast Arkansas

Concerning...Heavy rainfall...Flash flooding possible

Valid 281704Z - 282104Z

Summary...A band of convection was taking shape/increasing in
coverage along an axis from Monroe to Natchez. Isolated instances
of flash flooding are possible with this activity as it moves
slowly northward this afternoon.

Discussion...Areas of 1-2 inch/hr rain rates were beginning to be
estimated per MRMS within a convective band extending from Monroe
to Natchez. These storms were in a distinctive warm-advection
environment, with southeasterly low-level flow maintaining both
upper 70s F dewpoints and 2+ inch PW values - both supporting
heavy rainfall. Destabilization east of the ongoing convective
band was also aiding in its intensification, while ascent
associated with a mid-level trough over Oklahoma was also
providing ascent for deep updrafts. Slow northward storm motions
and localized mergers/training will both contribute to areas of
2-3 inch/hr rain rates in a few spots through 19-20Z.

The rain rates were falling on areas of relatively high FFG, with
thresholds of 2.5-3 inch/hr noted across the discussion area. Any
flash flood potential in the discussion area should be isolated
and primarily tied to precipitation over sensitive/low-lying or
urbanized areas. Convection will likely be diurnally driven, and
may eventually be impacted by maturing convection over far
southern MS and expanding cold pool/stabilization processes -
especially in southern parts of the discussion area.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4z9cZ38byOwjuerr0q4JER0Kel9y8sSOjAFJkAdlZ-Sr-iRlmTpTGKuaPyaWA0NGTWhj= XPp7DnpCQjL6Ew8hs8HtGi0$ for graphic product...

ATTN...WFO...JAN...LIX...LZK...SHV...

ATTN...RFC...ORN...NWC...

LAT...LON 33669021 32308969 31009136 32669228 33459195=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 282110
FFGMPD
ORZ000-290230-

Mesoscale Precipitation Discussion 0268
NWS Weather Prediction Center College Park MD
508 PM EDT Thu May 28 2026

Areas affected...central OR

Concerning...Heavy rainfall...Flash flooding possible

Valid 282107Z - 290230Z

Summary...Increasing thunderstorms coverage through the remainder
of the afternoon into the evening may lead to areas of flash
flooding across portions of central OR. Hourly rainfall over 1
inch is expected in a few locations along with 15-minutes rates of
0.25 to 0.75 inches. Total rainfall in a few locations may reach 2
inches.

Discussion...GOES West visible imagery showed the early stages of
convective development across southwestern ID into southeastern
OR, located north of an anomalous closed low centered over CA/NV.
Surface heating to the north of cloud cover over the southern
third of OR was contributing to decreasing convective inhibition
with MLCAPE of 500-1500 J/kg via 20Z SPC mesoanalysis data. Shear
parameters were sufficient for storm organization with individual
cell motions forecast from the E to NE, while clusters should have
more of a SE to NW movement. Any supercell structures would have
the slowest motions at ~15 kt (with other cell types faster), but
the combination of potential mesocyclones and the anomalous
moisture (PWs of 0.8 to 1.1 in the pre-convective environment)
will support precipitation efficiency and locally higher rainfall
rates.

Water vapor imagery identified a northward advancing shortwave
spoke over northeastern NV, on the eastern side of the closed low,
advancing toward southeastern OR. As this feature approaches
through 00Z, increasing DPVA and diffluence aloft should increase
convective coverage over central OR with an organized region of showers/thunderstorms likely developing through 03Z. Embedded
hourly rainfall prior to and within the forecast convective
cluster are expected to surpass 1 inch but with 15-minute rates of
stronger cells in the 0.25 to 0.75 inch range. Given FFG across
much of OR, east of the Cascades, is only 1 to 1.5 inches in 1
hour (slightly lower/higher in various locations), some areas of
flash flooding will be possible as cell coverage and merger
potential increases through the evening. Due to fairly dry
antecedent conditions, flash flood potential will be most likely
across any urban areas or sensitive burn scar locations.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!88BI5Xzob7MxRvS0a25idYdXqE-cOwuq7lB0LOgElIXBl2sGfABzBF71XNlxVXetnUyq= PXGl_Rj_QaMCghUnUOQiV5o$ for graphic product...

ATTN...WFO...BOI...MFR...PDT...PQR...

ATTN...RFC...PTR...RSA...NWC...

LAT...LON 45561958 45491897 45301828 44891795 44201824=20
43431888 42752000 42392114 42322202 42432242=20
42682253 43092260 43512258 43962249 44472229=20
45092188 45212141 45472053=20

=3D =3D =3D
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AWUS01 KWNH 282300
FFGMPD
TNZ000-MSZ000-MOZ000-ARZ000-290455-

Mesoscale Precipitation Discussion 0269
NWS Weather Prediction Center College Park MD
659 PM EDT Thu May 28 2026

Areas affected...southern MO/northern AR to the Lower MS Valley

Concerning...Heavy rainfall...Flash flooding possible

Valid 282258Z - 290455Z

SUMMARY...A few areas of flash flooding will continue to be
possible across portions of central to eastern AR, possibly
extending into southern MO, far southwestern TN and northwestern
MS. Hourly rainfall of 1 to 2+ inches and additional totals of 2
to 4 inches are expected through 05Z.

DISCUSSION...2230Z radar imagery across southeastern AR into
south-central MO showed an axis of slow moving thunderstorms with
an outflow boundary slowly edging eastward. Meanwhile,
thunderstorm activity has picked up over the past few hours from
northeastern AR, northward into southern MO. In addition to the
surface outflow boundary, larger scale low level convergence has
been contributing to a SSE to NNW axis of thunderstorms across AR,
with mean steering flow oriented parallel to the convergence axis
allowing for training of cells. Earlier hourly rainfall was 1 to
2+ inches with 6-hr MRMS estimates of 3 to 5 inches over portions
of northern AR. While the coverage of heavy rain has diminished
compared to earlier in the afternoon, a flash flood threat
remains.

SPC mesoanalysis data from 22Z showed that 1000-2000 J/kg MLCAPE
remained over the eastern half of AR into adjacent portions of
TN/MS. Aloft, a slow moving mid-level trough axis over western KS
into southeastern OK was favoring a divergent and diffluent flow
regime from MO/AR to the MS River.

While not as contiguous as earlier, low level convergence
(possibly fragmented sections) will continue to support localized
heavy rain across the region into the early overnight hours. The
primary and nearest term threat will exist across the northeastern
quadrant of AR where ongoing thunderstorm activity was in place.
Secondly, there is potential for increased low level convergence
to the north of a 925-850 mb low located over northeastern LA,
inferred via loops of visible satellite imagery, VAD wind data and
RAP analyses. This farther south flash flood threat is less
certain in occurrence, placement and timing, but may impact
eastern AR into the southeastern quadrant of the state and
northwestern MS after 00Z. As with locations in northeastern AR,
portions of southeastern AR have also received well above average
rainfall over the past week (200 to 600 percent of normal),
contributing to greater potential for runoff due to additional
heavy rain.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6OkyWS4maAzPRRpDECelKxXgR0ZueCASmzfq5sFa1ifkC1UayacBZajSSejNDMixqn7q= KjZRvCS6bYw_-S8PoodmZD0$ for graphic product...

ATTN...WFO...JAN...LZK...MEG...PAH...SGF...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON 37389279 37369205 36689065 35638967 34928946=20
34038979 33419017 33009106 33139162 33849201=20
34669249 35379281 36049315 36899310=20

=3D =3D =3D
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AWUS01 KWNH 290159
FFGMPD
MTZ000-IDZ000-ORZ000-WAZ000-290700-

Mesoscale Precipitation Discussion 0270
NWS Weather Prediction Center College Park MD
958 PM EDT Thu May 28 2026

Areas affected...northern OR into southern/southeastern WA and
northern ID

Concerning...Heavy rainfall...Flash flooding possible

Valid 290156Z - 290700Z

Summary...An isolated to widely scattered flash flood threat will
linger across northern OR into southern/southeastern WA and
northern ID over the next 3-5 hours. Potential will exist for peak
hourly rain of 1 to 1.5 inches and isolated totals up to 2 inches
through 07Z.

Discussion...GOES West infrared imagery and GLM data showed a SW
to NE oriented axis of thunderstorms advancing northwestward
across central to northern OR at 0145Z. Cells to the northeast of
this region across northern ID and western MT were more discrete
in nature but a few smaller clusters were beginning to form. While
instability had decreased across much of central OR, there
remained impressive MLCAPE from northern OR into eastern WA and
northern ID of 1000 to 2000+ J/kg according to the 00Z OTX RAOB
and recent SPC mesoanalysis (highest in the southern ID Panhandle,
south of I-90). PW values were also anomalously high at 0.9 to 1.2
inches over much of the region.

With sunset, the onset of nocturnal cooling at the surface is
expected to stabilize the low levels and reduce ongoing widely
scattered convective activity over western MT into portions of the
ID Panhandle. However, strong ascent ahead of a mid to upper-level
shortwave spoke advancing into southeastern OR (related to a large
closed low centered over CA/NV), will maintain areas of
thunderstorms as they continue to advance toward the north and
west within a broken axis. Embedded stronger cores within this
convective axis will be capable of producing 1 to 1.5 inches of
rain in an hour or two, resulting in isolated to widely scattered
flash flooding. This threat will be greatest where heavy rain
overlaps with urban locations, sensitive burn scars or otherwise
locally sensitive terrain.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7wtmhWdR1qrm0Le6723KvtMvEqdLZ2gpzeoNRb5GleYP5qq5r1ENBHO-xHcBRxQAnk92= RkggVYsKppa9_VqPeus9l5s$ for graphic product...

ATTN...WFO...BOI...MSO...OTX...PDT...PQR...SEW...

ATTN...RFC...PTR...NWC...

LAT...LON 48651699 48421627 47831569 47021552 46101625=20
45171702 44861888 44682017 44032116 43992185=20
44402206 45452197 46742136 47912036 48511839=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 291053
FFGMPD
MOZ000-ARZ000-291452-

Mesoscale Precipitation Discussion 0271
NWS Weather Prediction Center College Park MD
652 AM EDT Fri May 29 2026

Areas affected...northern Arkansas, southern Missouri

Concerning...Heavy rainfall...Flash flooding possible

Valid 291052Z - 291452Z

Summary...Scattered showers and occasional thunderstorms were
drifting slowly northward while producing locally heavy rainfall.=20
The combination of wet grounds from yesterday's rainfall and
locally sensitive terrain poses an isolated flash flood risk this
morning.

Discussion...Scattered convection was drifting north-northwestward
across the discussion area within a distinct warm-advection
regime. The convection was embedded in an environment
characterized by 1.8 inch PW values, 500-1000 J/kg MUCAPE, and
low-level confluence - supporting occasionally strong updrafts.=20
Most cells exhibited enough forward speed to keep rain rates at
around 1 inch/hr or lower, though a few spots where local
training/backbuilding has increased rain rates to near FFG --
particularly near Pope County/Russellville, AR over the past hour.
Occasional, yet isolated, flash flood potential will exist in
this regime in the near term.

Models suggest that ongoing activity will probably experience a
decreasing trend in convective coverage through the morning as
low-level flow/confluence decreases. Flash flood potential will
probably peak over the next couple hours, before decreasing
gradually through 14Z/9a central.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!__nBIANuDzfKkZyT0i-iNXyOhKrlv6eY-yQC0EyjO2bBQO20_hGB-7ahnCHTf2RmnT2y= 05ztim2FXaNSILOVTvVMdlc$ for graphic product...

ATTN...WFO...EAX...LSX...LZK...PAH...SGF...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 38579243 37529122 36189091 34869145 34369263=20
35729413 37539432 38489421=20

=3D =3D =3D
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AWUS01 KWNH 291801
FFGMPD
TNZ000-KYZ000-MSZ000-MOZ000-ARZ000-300000-

Mesoscale Precipitation Discussion 0272
NWS Weather Prediction Center College Park MD
200 PM EDT Fri May 29 2026

Areas affected...southern Missouri, much of Arkansas, western
Tennessee, northwestern Mississippi

Concerning...Heavy rainfall...Flash flooding possible

Valid 291800Z - 300000Z

Summary...Afternoon heating has resulted in a recent increase in
convective coverage across the discussion area, with flash
flooding possible on an isolated basis.

Discussion...Surface heating across much of Arkansas and the
presence of modest ascent aloft associated with an overhead
mid-level trough has resulted in renewed development of
thunderstorm activity across the discussion area. The environment
supporting thunderstorm activity remains moist (1.7+ inch PW
values), with surface heating now fostering 1000-1500 J/kg MLCAPE
- highest across Arkansas. Shear/steering flow aloft is weak,
resulting in slow-moving convection and locally heavy rain rates.=20
MRMS has already estimated spots of 1-2 inch/hr rain rates near
some storms. Additionally, rainfall was occurring in/near areas
that experienced heavy rain and flash flood impacts yesterday
between Little Rock and Harrison. FFG thresholds are low along
this axis, and may be readily exceeded at times given the
aforementioned regime.

Convective coverage will continue to expand gradually with time,
although eventually, widespread convective overturning should
result in a gradual lessening of convective (and flash flood) risk
toward evening/00Z. In the meantime, areas of flash flooding are
possible on at least an isolated basis.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8LRCiP-9W9fURQ-J9ksDi5qmMelq9TNwp_fGy2sbVpEbaMLub6mZoiemghWOSGwM6Gry= qkdKDZwMwAP03n-fGCLoPwk$ for graphic product...

ATTN...WFO...EAX...JAN...LSX...LZK...MEG...PAH...SGF...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 38739267 38449204 37769007 36708922 35488906=20
33419095 33939255 34629341 36529399 38159422=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 291816
FFGMPD
SCZ000-GAZ000-ALZ000-300015-

Mesoscale Precipitation Discussion 0273
NWS Weather Prediction Center College Park MD
215 PM EDT Fri May 29 2026

Areas affected...portions of Georgia

Concerning...Heavy rainfall...Flash flooding possible

Valid 291815Z - 300015Z

Summary...Strong convection has focused along a subtle confluence
zone extending from Atlanta to Macon to Brunswick. Convection
along this axis is slow-moving, with heavy rainfall potentially
leading to a few instances of flash flooding.

Discussion...Strong surface heating along a weak low-level
confluence zone from Atlanta to Macon to Brunswick has allowed for
strong thunderstorms to develop and intensify over the past couple
hours. The storms are in a very weakly sheared environment, with
2 inch PW values, 2000 J/kg MLCAPE, and slow movement encouraging
local areas of 1.5+ inch/hr rain rates especially from Macon
southeastward. These rates were falling on areas of 2-2.5 inch/hr
FFG thresholds (locally lower near Atlanta and northwestern
Georgia). The overall regime supports areas of isolated instances
of flash flooding - especially in/near low-lying and sensitive
locales.

With time and as thunderstorms mature, convective coverage will
expand, with spots of 2 inch/hr rain rates becoming more common.=20
Flash flooding will also become more of a concern given the slow
storm movement and tendency for local mergers.=20

Much of this activity will be diurnally driven, with any weakening
trend of convection dictated by any 1) loss of surface insolation
and 2) degree of convective overturning/stabilization. Flash
flood potential will exist through 00Z/8p eastern on an isolated
to scattered basis.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8H_qwgSQlJffD4J_iFU1VooC1N3PcFsj1inwI--wTbOOaoxJbpPYzi3rXNB8wLKhiTU6= 9oFY5vSUWcwSXsH0whRxiow$ for graphic product...

ATTN...WFO...BMX...CAE...CHS...FFC...JAX...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 34728483 34038364 33478230 32868147 31878111=20
30948145 30808229 31508430 32678510 34538545=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 300111
FFGMPD
TNZ000-ALZ000-MSZ000-ARZ000-300700-

Mesoscale Precipitation Discussion 0274
NWS Weather Prediction Center College Park MD
910 PM EDT Fri May 29 2026

Areas affected...northern MS into western TN and eastern AR

Concerning...Heavy rainfall...Flash flooding possible

Valid 300107Z - 300700Z

SUMMARY...Isolated flash flooding will be possible through 07Z
from slow moving thunderstorms from western TN into northern MS
and far eastern AR. Potential for hourly rainfall of 1 to 3 inches
will exist.

DISCUSSION...01Z radar imagery across the Lower MS Valley showed
scattered thunderstorms in the vicinity of I-40 from eastern AR
into western TN. Many of the cells were slow moving with peak
hourly rainfall of 1 to 2 inches (locally higher) per MRMS
estimates. Water vapor imagery showed the activity was focused
near a smaller scale vorticity max over southwest TN, part of a
larger upper-level trough axis/closed low over the region, slowly
advancing east. The environment remained moist and unstable with
MLCAPE of 1000 to 2000+ J/kg and PWs of 1.8 to 2.1 inches via 00Z
SPC mesoanalysis data and neighboring sounding data.

Over the next few hours, areas of slow moving thunderstorms are
likely to continue given the remaining instability and upper level
forcing in place. Mean steering flow is rather weak, ~10 kt over
north-central MS and less than 10 kt along the AR/TN border, which
will allow for slow moving cells. Some modest nocturnal
strengthening of 850 mb winds is expected over northern MS through
06Z (10-15 kt), which may act to support backbuilding/upstream
development of any thunderstorms across the region. Hourly
rainfall of 1 to 2 inches should be common with any thunderstorms,
but isolated hourly rainfall totals near 3 inches cannot be ruled
out, especially with any training.

While the occurrence of these high rain rates should remain
localized/isolated in coverage, there is enough of a concern to
highlight this potential for flash flooding over the region, which
is expected to continue through 07Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4ktb16KhUdN7stNy_wOCFChC9C3RYAJUp9XjJJ79bVtMg683Q5IJA-gdoeVqOl2wHnbm= 1cqQvt9dpVOZb67xtvABDco$ for graphic product...

ATTN...WFO...HUN...JAN...LZK...MEG...OHX...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 36448926 36278813 35478802 34218833 33358874=20
32908923 32858976 32929021 33149060 33369086=20
34019101 35049086 36018969=20

=3D =3D =3D
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AWUS01 KWNH 300151
FFGMPD
NCZ000-GAZ000-TNZ000-ALZ000-300730-

Mesoscale Precipitation Discussion 0275
NWS Weather Prediction Center College Park MD
950 PM EDT Fri May 29 2026

Areas affected...western GA into far eastern AL, eastern TN and
far western NC

Concerning...Heavy rainfall...Flash flooding possible

Valid 300149Z - 300730Z

Summary...Flash flood potential will linger across portions of
eastern AL/western GA into portions of the TN Valley and southern
Appalachians through 0730Z. Slow movement of cells will support
potential for localized hourly rainfall of 1 to 3+ inches.

Discussion...0130Z radar imagery showed a few lingering showers
and thunderstorms over west-central and northeastern GA with
MRMS-estimated hourly rainfall of 2 to 3 inches on a very isolated
basis. Much of central GA has been worked over by earlier
convection, reducing available instability and increasing low
level inhibition, limiting near term concerns for additional heavy
rain. However, the western portion of GA into eastern AL remained
unstable with ~1000 to 1500 J/kg MLCAPE via 01Z SPC mesoanalysis
data with little to no inhibition. The approach of a mid to
upper-level trough from the west may provide forcing for the
development of additional showers/thunderstorms, possibly
increasing in the 03-06Z time frame. The reflection of the ongoing
ascent ahead of the upper trough was represented by a small
cluster of weakening thunderstorms over south-central AL as of
0130Z.

Farther north, radar imagery over the past 30 minutes has shown an
expansion in the coverage of showers/thunderstorms over eastern
TN. A relative max in MLCAPE resided over the region with 500-1500
J/kg via the 01Z SPC mesoanalysis. While shear was lacking for
storm organization, deeper layer mean winds were weak at less than
10 kt from the southwest which will allow for 1 to 2+ inch
rainfall (in excess of area FFG), especially where upstream
development occurs.

Moisture across the region was high with PWs ranging from 2.2
inches over south-central GA (near a stationary front) to 1.6
inches in eastern TN. Earlier observed gauge reports in portions
of GA showed 3 to 3.5 inches in an hour, a testament to the very
moist and efficient airmass in place over the region. The weak
steering flow over AL/GA/TN will be supportive of slow moving
cells with the potential for backbuilding/upstream development,
supportive of isolated 2+ in/hr rainfall.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_eq5lwqiNdKtOJDzPBGVgwcZ75ZIs_t_eMwu4KMYFIKmMus9vJkRqpejISF1SyKBDNjH= cNJ-gIZANzq3t31g5FCw2BE$ for graphic product...

ATTN...WFO...BMX...FFC...GSP...HUN...MRX...OHX...TAE...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36478321 36288234 35778243 35488300 35288326=20
34938352 34408363 32978332 32228304 31658357=20
31608460 31818527 32288553 33138580 34108578=20
35028550 35798499 36398402=20

=3D =3D =3D
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AWUS01 KWNH 300408
FFGMPD
MTZ000-300700-

Mesoscale Precipitation Discussion 0276
NWS Weather Prediction Center College Park MD
1207 AM EDT Sat May 30 2026

Areas affected...Eastern Montana

Concerning...Heavy rainfall...Flash flooding possible

Valid 300406Z - 300700Z

SUMMARY...A nearly stationary line of storms is producing 2.5
in/hour rainfall rates. Flash flooding possible.

DISCUSSION...A nearly stationary line of storms caught on a trough
near a surface low over eastern Montana is producing rainfall
rates to 2 inches per hour on the county line between Valley and
Phillips Counties. The outflow boundary has pushed well east of
the storms, and should eventually work to cut off the inflow,
however due to the proximity of a low level jet, the storms have
been maintaining themselves just west of Glasgow. 1-hourly flash
flood guidance shows 1 hour amounts are between 1.25 and 1.5
inches in the area of the storms, so ongoing rainfall is exceeding
those amounts.

High-resolution guidance suggests that as the storms use up the
instability, which is over 1,500 J/kg in SBCAPE and near 2,000
J/kg in MUCAPE, the storms should detach from the trough, weaken,
and push north into Canada. It should be noted that the guidance
generally struggles with these kinds of mesoscale features. In
this case, given the evident outflow boundary outracing the storms
now by tens of miles, it appears likely that the storms' inflow
should soon be cut off, resulting in weakening.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8q5Gd4lJX1JfxFZFqrpIuy-gyj2i10k8eeGy3LYXI8ki01aW-9iHW7TIQefqIL2hyJCd= V9f2iECWUgzPU4WtMaS_q8E$ for graphic product...

ATTN...WFO...GGW...

ATTN...RFC...KRF...NWC...

LAT...LON 49100644 49060599 48720571 48220575 47850617=20
47760666 47480704 47320718 47360770 47590787=20
47870780 48220782 48650781 49040772=20

=3D =3D =3D
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AWUS01 KWNH 300924
FFGMPD
VAZ000-TNZ000-KYZ000-301500-

Mesoscale Precipitation Discussion 0277
NWS Weather Prediction Center College Park MD
523 AM EDT Sat May 30 2026

Areas affected...Southern Kentucky to Eastern Tennessee

Concerning...Heavy rainfall...Flash flooding possible

Valid 300922Z - 301500Z

SUMMARY...Stationary front forcing a line of storms with erratic
cell motions but ample moisture. Localized flash flooding possible.

DISCUSSION...A stationary front denoted by a substantial moisture
gradient is providing the forcing for a line of storms to form
from southern Kentucky through eastern Tennessee. Weak, but
nonetheless sufficient southwesterly flow into the front is
allowing the moisture (PWATs as high as 1.9 inches in western
Kentucky) to lift into the developing line of storms. Since they
are both slow-moving and being reinforced by the moisture
advection, expect the storms to persist for the next several hours
until daytime heating works to disrupt the flow into the front, as
well as introduce competing forcing from diurnal heating, cold
pools, and in some areas, topography. This will result in a
gradual diminishing of the storms associated with the front itself
by late morning. While the front is stationary, since the overall
flow into the front is stronger from the moist southwest side of
the front, expect some northeastward drifting of the line of
storms through the morning.

HREF 6-hr FFG exceedance probabilities show as high as a 40-45
percent in portions of south-central Kentucky, and another local
maximum in eastern Tennessee of 25-30 percent through 15Z. Cell
mergers northwest of Knoxville are already causing flash flooding,
and expect with chaotic flow along the front that additional cell
mergers will occur into southern Kentucky through the morning.
What few pieces of high-resolution guidance are resolving the line
of storms suggest that there will be rather rapid weakening of the
storms by late morning for the aforementioned reasons, which will
diminish the flash flooding threat.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7BouVMkgsq46_v2WTmBJdvBssIRjr-o--KZT97NbklbeuD66C9VPViWmoU5GeWiqxAIN= 6xbFYMeR1AmgC56y8orme6A$ for graphic product...

ATTN...WFO...JKL...LMK...MRX...OHX...PAH...

ATTN...RFC...ORN...TIR...NWC...

LAT...LON 37878610 37738537 37548494 37418409 37198318=20
36948243 36678187 36368205 36088271 35758336=20
35608382 35858436 36238504 36498571 36498579=20
36538581 36868663 37008689 37418701=20

=3D =3D =3D
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AWUS01 KWNH 301540
FFGMPD
MTZ000-302138-

Mesoscale Precipitation Discussion 0278
NWS Weather Prediction Center College Park MD
1139 AM EDT Sat May 30 2026

Areas affected...portions of Montana

Concerning...Heavy rainfall...Flash flooding likely

Valid 301538Z - 302138Z

Summary...Scattered thunderstorms are increasing in coverage while
migrating toward central Montana. These trends will continue for
several hours, posing a risk of flash flooding through 21Z/2p
mountain time.

Discussion...Areas of surface heating have led to sufficient
destabilization (areas of 500-1000 J/kg MLCAPE) for scattered
thunderstorm activity from west of Jordan to east of Billings and
eastward along the MT/WY border region. The storms were migrating
slowly westward at around 10-15 knots due to easterly steering
flow on the norther periphery of a distinct mid/upper low near
northeastern UT. Northeasterly low-level trajectories were aiding
in upslope/subtle orographic ascent across the discussion area,
while low 60s F dewpoints and 1+ inch PW values were supporting
heavy rainfall beneath persistent and locally backbuilding
convection. Rain rates were peaking at around 1 inch/hr per MRMS,
which 1) isn't surprising given the regime and 2) approaching FFG
thresholds especially closer to central Montana.

With time, continued insolation/destabilization within the
low-level upslope regime across eastern Montana will continue to
support a gradual expansion of convective coverage. Storms could
become numerous after 18Z/11a mountain time, with continued areas
of 1 inch/hr rates exceeding FFG especially across central
Montana. Lighter rain rates along I-90 west of Billings, along
I-15 through Helena and Great Falls, and across northern Montana
near Glasgow could also cause runoff issues given low FFG
thresholds in those areas. Flash flooding is expected in several
areas today.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7OW31X31s4WnAYzd8HPTbWxtzD6kqGAZA_JPLx9KvErdiNj4Ux8GgekJPeGr1w5wPOB2= 1Ajj29GfXVrFPFrHCpkAjoI$ for graphic product...

ATTN...WFO...BYZ...GGW...MSO...TFX...

ATTN...RFC...KRF...PTR...NWC...

LAT...LON 48991242 48970930 48820679 48040625 46830571=20
45710501 45040534 45000878 45041107 45531216=20
46821309 48731333=20

=3D =3D =3D
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AWUS01 KWNH 302032
FFGMPD
MOZ000-OKZ000-KSZ000-310030-

Mesoscale Precipitation Discussion 0279
NWS Weather Prediction Center College Park MD
431 PM EDT Sat May 30 2026

Areas affected...Southeast Kansas...Southwest Missouri

Concerning...Heavy rainfall...Flash flooding possible

Valid 302030Z - 310030Z

SUMMARY...Slow-moving thunderstorm clusters will continue to track east-southeast across southeast Kansas and southwest Missouri
through early evening. Rainfall rates of 1 to 2 in/hr may yield
localized totals of 2 to 4 inches, making isolated flash flooding
possible.

DISCUSSION...Animated satellite and regional radar imagery show an
expanding axis of convective clusters stretching across southeast
Kansas into southwest Missouri. These clusters have recently
exhibited rapidly cooling cloud tops, signaling robust updraft
strength and active vertical development. Supported by a pooling
moisture environment (PWATs climbing toward 1.4?1.6 inches) and
moderate diurnal destabilization, these storms are highly
efficient rainfall producers, with recent MRMS data estimating
localized rates of 1 to 2 in/hr.

The kinematic environment is characterized by weak mid-level
steering flow and small upwind propagation vectors, leading to
slow, grinding storm motions toward the east-southeast. While
high-resolution model guidance exhibits typical summer spatial
discrepancies, with the RRFS aggressively favoring 2 to 4 inch
localized pockets through 00Z and the HRRR taking a more
conservative 1 to 2 inch approach, the current observational trend
strongly supports the higher-end rainfall potential where cells
manage to cluster or briefly train.

Given the somewhat moist antecedent soil environment indicated by
recent NASA SPoRT soil moisture data, infiltration capacities are
moderately reduced. While a widespread event is not anticipated
due to the lack of strong synoptic forcing, these slow-moving 1 to
2 in/hr rates will be capable of producing isolated short-term
flash flooding, primarily concentrated across localized low-lying
areas, small creeks, and vulnerable urban intersections.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6fssWYIZLBkibj5b4UX5CVsTI0uo5AKNv1vlrjdUfAz9pK7ZKIwq_WrN4vsrUmOhG4e4= sEbK-j4fxEbRFdipxU57RGs$ for graphic product...

ATTN...WFO...EAX...ICT...SGF...TOP...TSA...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON 38109564 38099400 37739308 37159290 36769326=20
36699437 37169581 37769603=20

=3D =3D =3D
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AWUS01 KWNH 302156
FFGMPD
NEZ000-SDZ000-NDZ000-MTZ000-WYZ000-310355-

Mesoscale Precipitation Discussion 0280
NWS Weather Prediction Center College Park MD
555 PM EDT Sat May 30 2026

Areas affected...Far Northwest Nebraska...Northeast
Wyoming...Western South Dakota...Central and Eastern Montana

Concerning...Heavy rainfall...Flash flooding likely

Valid 302155Z - 310355Z

SUMMARY...Broken clusters of heavy showers and thunderstorms will
continue to expand and organize across portions of far northwest
Nebraska, northeast Wyoming, western South Dakota, and into
central/eastern Montana this evening. Fueled by highly anomalous
moisture and enhanced surface convergence along an elongated axis
of surface low pressure, rainfall rates of 1 to 2 in/hr will be
capable of producing localized 2 to 3+ inch totals. Flash flooding
is likely, particularly across sensitive high-terrain basins.

DISCUSSION...Recent RAP mesoscale analysis and satellite imagery
depict a robust upper-level low centered over Wyoming, embedded
within an elongated trough stretching across the northern Rockies.
This low is projected to slowly lift northward through the evening
hours, providing widespread, deep-layer forcing and ascent.
Concurrently, a potent low-to-mid-level fetch is continuously
transporting a deeply anomalous moisture plume from the Central
Plains northwestward. Precipitable Water (PW) values within this
plume are exceptionally high for late May, running 2 to 3 standard
deviations above the climatological mean.

At the surface, the latest mesoscale guidance indicates the
organization of an elongated surface low pressure center
stretching from northeast Wyoming up through southeast and central
Montana. This feature is significantly enhancing low-level
convergence across the region. Along and east of this boundary, an
axis of moderate instability has materialized, with MLCAPE values
locally exceeding 1000 J/kg extending down into northeast Wyoming,
the Black Hills of western South Dakota, and far northwest
Nebraska.

Driven by this combination of deep synoptic lift, enhanced surface
convergence, and high moisture efficiency, broken to locally
organized convective clusters are expected to produce intense
hourly rainfall rates of 1 to 2 in/hr along this corridor. The
consensus of the latest high-resolution guidance, including the
18Z HREF, 18Z REFS, and recent RRFS runs, strongly favors
localized additional accumulations of 2 to 3 inches through the
late evening.

The 18Z HREF indicates areas of 40 to 60+ percent probabilities of
exceeding 3-hour Flash Flood Guidance (FFG), particularly across
central Montana and the Black Hills. Given some of the flashy
nature of the regional terrain and the high efficiency of these
convective cores, areas of rapid runoff are expected which will
tend to lead to at least some areas of flash flooding.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_7I_3W3cBH4sMFgh7FCFr6xlRXGPvPZy5pBUVynG0TWaOJz6oQA44_CoEtqXaSsqZUrI= 0uthYGrDFobxeObCh5ktqAo$ for graphic product...

ATTN...WFO...BIS...BYZ...CYS...GGW...LBF...RIW...TFX...UNR...

ATTN...RFC...KRF...NWC...

LAT...LON 49360786 48810655 47960486 45980291 45230218=20
43850163 42760206 42490315 42670366 43730460=20
44370529 44880727 44750918 45050999 45951047=20
47221004 48700989 49260913=20

=3D =3D =3D
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