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FOUS11 KWBC 011800
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
100 PM EST Sun Feb 1 2026

Valid 00Z Mon Feb 02 2026 - 00Z Thu Feb 05 2026

...Northern Plains through the Great Lakes...=20
Days 1-2...

A shortwave on the upstream side of an amplified trough (500mb
heights below the 1st percentile according to NAEFS) will dig
southeast from Saskatchewan while a secondary shortwave deepens
into a closed low over Ontario. Together, these features will drive
a surface cold front eastward from the Northern Plains to the Great
Lakes D1 before continuing into the Ohio Valley D2. The overlapping
ascent between height falls/PVA and low-level convergence, along
with modest frontogenesis and subtle WAA will result in an axis of
light to at times moderate snow, with the heaviest likely occurring
in response to lake enhancement east of Lake Michigan and across
the U.P. in the NW snow belts. WPC probabilities are modest overall
as available moisture is limited, but locally as much as 4" of snow
is possible (10-30%) across the U.P. and far NW L.P., with less
than 2" expected elsewhere. Additionally, some light freezing rain
is also possible driven by dryness within the DGZ, and WPC
probabilities for 0.01+" of ice are 10-30% across portions of the
Dakotas D1.


...Ohio Valley, Central Appalachians, and Mid-Atlantic...=20
Days 2-3...

A fast moving shortwave diving out of Alberta will drop southeast
around the western CONUS high and into the Mid-Mississippi Valley
Tuesday morning. This shortwave will amplify, at least subtly, as
it translates to the southeast, maintaining a positive tilt but
interacting with a cold front digging across the Ohio Valley. At
the same time, a subtropical jet streak draped along the Gulf Coast
will gradually intensity in response to the trough amplification,
and begin to pivot poleward, with the response to this evolution
being a surge in moisture lifting out of the Gulf noted by a strung
out theta-e ridge from the FL Panhandle into the Mid-Atlantic. This
moisture return will be aided by at least modest WAA, and the
guidance has trended upward just a bit in its QPF potential, and
has shifted northward somewhat as well.

The WAA lifting isentropically atop the cold front into the colder
airmass should result in a swath of light to moderate snowfall,
although locally heavier rates are possible due focused fgen into
the deepening DGZ, and this is reflected by significant spread in
the latest WSE plumes, despite a focus of mostly light snowfall
amounts. Current WPC probabilities are low (10-30%) D2 for at least
2 inches across the Central Appalachians of WV (where upslope
enhancement is likely), and moderate (30-50%) in that same area D3
suggesting localized totals of 4" are possible. Elsewhere, WPC
probabilities suggest moderate risk (30-70%) for more than 1 inch=20
across the lower Ohio Valley and a 10-30% for similar accumulations into
the Mid- Atlantic states including Washington, D.C.

Some light freezing rain is also possible with this wave as it
swings eastward, mostly due to loss of cloud ice vs warm nose
development, which could result in a swath of ice accretion above
0.01" (10-30% chance) from western KY/TN into VA/NC. Any ice is
hazardous, but this could be more problematic than usual due to
continued recovery efforts from the recent winter storms.


...Pacific Northwest...
Day 1...

A modest Pacific jet streak will lift northeast atop a west coast
ridge Monday, bringing with it a brief period of IVT exceeding the
90th climatological percentile according to NAEFS. A warm front
will push onshore and lift northeast concurrently with this jet
streak, leading to a brief period of enhanced WAA/precipitation
before snow levels climb rapidly into D2. This will result in a
period of rain and snow across the Washington Cascades, and
although snow level forecasts are generally above pass level, a few
inches of snow is possible between 3000-4000 ft before turning to=20
rain. WPC probabilities for 4+ inches of snow are above 70% only in
the higher Washington Cascades, but a few slushy inches of=20
accumulation is forecast at Stevens Pass leading to hazardous
travel Monday afternoon.

Weiss


...Winter Storm Key Messages are in effect. Please see current=20
 Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=
stKeyMessage_1.png__;!!DZ3fjg!9YRGIGSlDRwz1Kt4s7H_JQxQxrQrLi-hlxXkhTcc2PeqV=
OUwi_taivHgsFXvEnCrMLHMjTJRc9mduyxC6l5q8VK4ssU$=20



$$

=3D =3D =3D
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