Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Sun Oct 26 2025

Valid 00Z Mon Oct 27 2025 - 00Z Thu Oct 30 2025


...Cascades and Northern/Central Rockies...
Day 1...

The third and final shortwave trough axis with the troughing over
the Northwest the past couple of days is pushing over the OR coast
this afternoon. This axis reaches central MT by 18Z Monday and will
provide the focus for moderate to locally heavy snow over the
Cascades and northern Rockies that mainly tapers off for the
Cascades Monday morning and Monday evening for the northern
Rockies. Snow levels drop further under this trough, to around
3000ft in the WA Cascades tonight and the Bitterroots Monday
morning, and around 3500ft in the OR Cascades through Sawtooths of
ID and around Yellowstone (Absarokas, Tetons, Wind River) and about
4500ft for the Bighorns.

Day 1 WPC probabilities are high (50-80%) for >8" for the Tetons,
southern Absarokas, Wind River, and Bighorns while moderate
(40-60%) for >6" for the higher Cascades, Blue Mtns of OR,
Bitterroots and Lewis Range, Uinta of UT and the Medicine Bow/Park
Range along the WY/CO border.

Lee-side troughing should allow some higher elevation snow in
eastern WY and the Black Hills Monday evening.


...Washington Cascades...
Day 3...

A potent, but progressive low pushes across the BC coast Tuesday
night with a trough axis extending south over Washington State.
High snow levels around 8000ft Tuesday afternoon in the elevated
moisture plume quickly crash to around 4500ft by the time the
trough crosses and precip cuts off. Day 3 snow probabilities for
>6" are 20-40% around North Cascades NP.


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


Jackson