FOUS11 KWBC 070706
QPFHSD
Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
206 AM EST Sat Feb 7 2026
Valid 12Z Sat Feb 07 2026 - 12Z Tue Feb 10 2026
...Northeast & Mid-Atlantic... Day 1...
Extreme cold and dangerous wind chills overspread the Northeast
tonight and continue through Sunday with Key Messages in effect
and linked below.
The combination of an arctic cold front current racing through the
Ohio Valley/Interior Mid-Atlantic will combine with a strengthening
low pressure well offshore to produce extremely cold temperatures
and damaging winds for much of the region, with heavy snow for
parts of the area as well.
A shortwave driving the cold front southward will help generate
widespread light snow across New England and Long Island, but total
snowfall amounts are expected to be rather modest. Despite that,
briefly heavy snow rates combined with the rapidly increasing winds
will still result in impacts, especially to travel due to snow-
covered roads and low visibility. The greatest impacts, and likely
more substantial snowfall, is expected from far SW Maine, SE New
Hampshire, and along the eastern Coast of Massachusetts from Cape
Ann to Cape Cod where low-level convergence, onshore flow and
resulting ocean effect snow (OES) and an inverted trough will all
interact to enhance snowfall. There continues to be uncertainty as
to where the heaviest snowfall will occur. However, intense
snowfall rates of 1-2"/hr are possible (30-60% chance) thanks to
intense ascent into a lowering DGZ within the presence of some
instability. WPC probabilities are moderate (50-70%) for 4+ inches
from the Seacoast of NH through the Boston metro area, with locally
more than 8 inches possible (10-30% chance) and as reflected by
significant spread amongst the WSE plumes.
...Pacific Northwest and Northern Rockies... Days 1-3...
Mid-level trough positioned off the Pacific coast will slowly track
eastward today and Sunday, with the primary trough axis finally
pushing onshore Sunday night as a shortwave lifts onshore near the
CA/OR coast. This shortwave will then continue to track east while deamplifying, reaching the northern High Plains by the end of the
forecast period.
This trough evolution will be accompanied by a modest subtropical
jet streak arcing meridionally downstream to provide overlapping
synoptic ascent. This lift will occur into a moistening column as
persistent SW flow ahead of the shortwave/trough axis will provide
a long duration of IVT exceeding 250 kg/m/s, with IVT max
potentially exceeding 500 kg/m/s (50-60% chance) which will lead to
two rounds of heavy precipitation extending from Oregon through
the Northern Rockies. Snow levels within the strongest IVT plume
will be 6000-7000 ft thanks to pronounced WAA, but will steadily
fall to 3000-4000 ft Monday as a cold front, driven by the
aforementioned trough, progresses southeast. This will allow for
heavier and more impactful snow across the Northern Rockies than
what is anticipated in the Cascades due to lower snow levels. 2-day
WPC probabilities indicate the heaviest snow is expected in the
vicinity of Glacier NP in the Northern Rockies where they exceed
70% for 12+ inches, and locally as much as 2 feet is possible in
the highest terrain. Elsewhere, WPC probabilities are high (>70%)
for 8+ inches across the Absarokas and Tetons near Yellowstone NP,
the Blue Mountains of OR, and across the highest peaks of the WA
and OR Cascades.
Weiss
...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...
https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png
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* Origin: Capitol City Online (21:1/175)
