900
FOUS11 KWBC 030732
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
232 AM EST Mon Nov 3 2025

Valid 12Z Mon Nov 03 2025 - 12Z Thu Nov 06 2025

...Washington Cascades & Northern Rockies...
Days 1-3...

An active weather pattern resumes across the West as a shortwave
trough pushes in from the Pacific Northwest coast Monday night and
into Tuesday with a plume of modest 700-300mb moisture and a band
of weak 850-700mb WAA aloft. A lack of substantial antecedent sub-
freezing air-mass will keep heavy snow confined to the higher and
more remote elevations of the WA Cascades and northern Rockies.
However, accumulating snow is possible at some passes above 4500ft,
especially Stevens Pass in the WA Cascades. Snow levels will vary
by mountain range; from around 4000-5000ft in the WA Cascades,
Bitterroots and Lewis Range of NW MT to 8000ft for the Sawtooths in
ID, the Absaroka, Tetons, and around Yellowstone. Days 1-2 WPC
snow probabilities range between 50-80% for >8" across the WA
Cascades above 5000ft, while lower chances (30-60%) of >8" of snow
are likely to be confined to the higher terrain of the NW MT
Ranges.

As some residual light mountain snow persists on Tuesday, the
next system approaches the West Coast Tuesday night with a
moderate-to-strong atmospheric river directing an impressive plume
of moisture within strong 850-500mb WAA into the Northwest U.S
through Wednesday.. Aside from the taller peaks of the WA/OR
Cascades and Northern California`s mountain peaks, most snowfall
will reside above 5,000ft in elevation. Precipitation is likely to
spill over into the northern Rockies late Wednesday and into
Thursday morning with some accumulating snowfall in the Sawtooth,
Blue, Tetons, Bitterroot, and Lewis Ranges. The Sawtooth are the
only notable mountains that WPC probabilities shows having moderate
chances (40-60%) for snowfall totals >4" above 7,000ft.

...Northern New England Appalachians...
Days 1 & 3...

A pair of storm systems will traverse New England; one on Monday
and the other on Wednesday, will generate periods of snow in a
couple different fashions. Today, snowfall will largely be
generated via 850-700mb CAA and WNWrly upslope flow into the
northern Appalachians. Despite the CAA at low-levels, boundary
layer temperatures remain generally above freezing with the
exception of the peaks of the Adirondacks and White Mountains. WPC
probabilities show moderate chances (10-30%) for snowfall totals
>4" in these mountain ranges peaks, which includes most notably
Mount Washington.

By Wednesday, an amplifying shortwave trough exiting the Great
Lakes will generate healthy upper-level ascent over New England
that prompts the development of a low pressure system. This
developing storm system is a progressive one, but a modest plume
of moisture accompanying the storm gives rise to periods of snow
Wednesday night and into Thursday morning. The heaviest snowfall
likely occurs as the storms tracks over coastal Maine and strong
CAA and upslope NWrly flow envelops the Adirondacks, Green, and
White Mountains. Snow levels will drop more this go round compared
to Monday, dropping as low as 1,000ft from the Green Mountains on
north and east through western Maine. WPC probabilities show
moderate chances (40-60%) for snowfall >4" in parts of the Great
North Woods of northern New Hampshire and over western Maine. Mount
Washington is most likely to be the favorite to see the heaviest
snowfall, with low-to-moderate chances (20-40%) for snowfall totals
>8" at Mount Washington`s summit. Some hazardous travel conditions
on roadways are possible in the peaks of the Adirondacks and White
Mountain passes late Wednesday night into Thursday morning. Note
the forecast still has a high degree of uncertainty and a change in
forecast track and or intensity could result in changes in the
snowfall forecast.


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

Mullinax







$$