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FOUS11 KWBC 231947
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
247 PM EST Sun Nov 23 2025

Valid 00Z Mon Nov 24 2025 - 00Z Thu Nov 27 2025


...Pacific Northwest & Northern Rockies...
Days 1-2...

A Pacific shortwave trough is escorting a progressive, but potent,
frontal system into WA/OR/ID and northwestern MT today. As the
cold front traverses the Pacific Northwest, snow levels around
5000-6000ft this afternoon will drop to as low as 2,000ft on the
windward side of the Cascades tonight as precipitation. Even as the
upper-level trough exits east, lingering upslope flow could keep
light snow in the forecast through Monday afternoon. This would
affect many of the passes with at least some snow, and WPC
probabilities for >4" of snow are between 30-50% in both Stevens
and Snoqualmie Passes.

Farther east, as the aforementioned plume of mid-level moisture
tracks eastward, snow will also spread across northern ID into
western MT this afternoon through Monday as moisture associated
with the Pacific system passes through. Measurable snowfall will
stretch as far south as the Tetons and Absaroka with the peaks of
the Tetons north of Jackson, WY sporting moderate-to-high chances
(50-70%) for snowfall totals >8". The focus for the heaviest
snowfall resides along the Lewis Range tonight and through Monday
as snowfall rates become enhanced by easterly upslope flow due to
strengthening high pressure over southwest Canada. Snowfall rates
>1"/hr are possible at higher open passes (including Marias Pass).
Snow should taper off across all of the northern Rockies by early
Tuesday morning. WPC probabilities for >8" of snowfall are >70%
across the Lewis Range above 5,000ft. In the highest elevations of
the Lewis Range (>6,000ft), WPC probabilities show moderate chances
(40-70%) for snowfall totals >12". The WSSI does show Moderate
Impacts (hazardous travel conditions) in the Lewis Range, the
Bitterroots, the Crazy Mountains, and peaks of the MT Absaroka.

...Northern Cascades/Olympic Peninsula...
Days 2.5-3...

Following a brief lull in the action on Monday night and Tuesday
morning, the next Pacific system moves into western WA on Tuesday
at the nose of an 140kt 250mb jet. Unlike the storm system this
weekend, Canadian high pressure will provide a colder air-mass out
ahead of this next Pacific storm system that will support some
spotty freezing rain along the leeward slopes/valleys of the
Cascades and in the valleys of the Columbia River Basin over
northern WA. Snow levels will gradually rise as the warm front
lifts through Tuesday night into early Wednesday, but the surface
front will takes longer to cross the Cascades rather than the more
robust 700mb WAA nose that support the potential for icy
conditions east of the Cascades. Thanks to a longwave trough firmly
entrenched over the North Pacific, an extended moisture fetch into
the the Pacific Northwest provides a favorable setup for multiple
days worth of accumulating snow and ice that continues through
Wednesday afternoon. Through 00Z Thursday, WPC probabilities of at
least 6 inches of snow are >50% above about 4000ft, with as much as
4-6" of snowfall possible near Snoqualmie Pass.

...Northeast...
Day 1...

A clipper system rotating beneath the base of an broad upper-low
over Quebec will push quickly through northern NY/New England this
evening and exit to the east by Monday morning. QPF and the
resulting snowfall will be somewhat limited due to its fast
movement and the clipper being relatively moisture-starved, but
upslope enhancement will allow for anywhere between 1-4" of snow
across the Tug Hill, Adirondacks, and the Green and northern White
Mountains. WPC probabilities for at least 4 inches of snow remain
on the lower side (10-30%) in these areas generally above
1500-2000ft in the Adirondacks and Tug Hill. Despite the minor
accumulations, this system would still support snow covered roads
that could make for slippery driving conditions tonight and Monday
morning.

...Northern Plains & Upper Midwest...
Days 2-3...

The shortwave trough responsible for the snow across the Northern
Rockies to start the week moves into the northern High Plains by
Monday night. An 850mb low will form along a strengthening
925-850mb front over central ND, while a narrow inverted trough
axis forms on its western flank. By 12Z Tuesday, areas from
northeast MT to central ND will be enveloped in a band of
moderate-to-heavy snow that also includes increasingly gusty winds
as low pressure strengthens. As the low moves east, the TROWAL on
the western flank of the storm is likely to produce at least 1"/hr
snowfall rates during the daytime hours Tuesday, which combined
with wind gusts approaching 30 mph will cause poor visibility.
However, areas not beneath the deformation axis will struggle to
accumulate given marginal boundary layer temperatures and lesser
SLRs. Expect a tight gradient in snowfall totals, where beneath the
TROWAL WPC probabilities over central ND show low-to- moderate
chances (30-50%) for snowfall totals >6" through Tuesday evening.
Across northeast ND and southern ND, those probabilities drop to
low chances (10-30%) for >6".

By Tuesday evening, the winter storm will strengthen as most
guidance agrees that a closed 500 low develops as it heads for
central MN. The 500mb low will be embedded within a broad 500mb
trough that takes on a negative tilt, fur The heaviest snowfall is
likely to occur just north of the 700mb low track, which places
northern MN in the sweet spot for heavier totals. Beneath the
strengthening TROWAL, snowfall rates of 1-2"/hr are possible late
Tuesday afternoon and into Tuesday night. As the storm tracks into
northern WI Tuesday night, ENErly winds will accelerate off Lake
Superior and introduce more low-level moisture and convergence over
the MN Arrowhead. Snowfall rates of 1-2"/hr are anticipated and
should accumulate efficiently do the bulk of the snow in northern
MN coming over night. Snow will also fall heavily over northwest WI
and the western Michigan U.P. Tuesday night and continue into
Wednesday as CAA over Lake Superior kick up lake-enhanced snowfall.

WPC probabilities for >6" of snow are >50% across north-central MN
with low-to-moderate chance probabilities (30-50%) for >12" of
snowfall in the MN Arrowhead. The area most likely to see >12"
snowfall amounts are portions of Michigan`s far western U.P.,
including the Porcupine Mountains, where WPC probabilities show
moderate chances (40-60%) for >12" of snowfall. Across much of ND,
most snowfall amounts will range between 2-6", but on which end of
those amounts portions of the state witness will depend heavily on
the placement of the banded areas of snowfall. Interests in the
Northern Plains and Upper Midwest should keep a close eye on the
forecasts from their NWS WFOs and WPC in the coming days given this
storm could prove a headache for those traveling in the lead up to
Thanksgiving.


The probability of significant ice across the CONUS is less than
10 percent.

Mullinax





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