Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
341 PM EDT Sat Oct 25 2025

Valid 00Z Sun Oct 26 2025 - 00Z Wed Oct 29 2025


...Pacific Northwest to the Central Rockies...
Days 1-2...

Main shortwave trough axis rounding low from deep Gulf of Alaska
low is crossing the OR/WA coast this afternoon. Snow levels are
quickly dropping to around 4500ft over the Cascades and will drop
to around 5000ft over the Northern Rockies this evening. A
reinforcing shortwave trough axis crosses the OR/WA coast Sunday
morning with continued onshore flow with decreasing precip rates
then through Sunday night.

Heavy snow rates of 1-2"/hr persist through tonight along the
Cascades per the 12Z HREF which combined with snow levels dropping
to around 3500ft should result in moderate winter weather impacts
for most mountain passes in the Cascades tonight. One to two feet
of snow should occur tonight in the Cascades well above pass
level.

The precipitation focus shifts inland Sunday with moderate to
locally heavy rates in terrain of the northern Rockies (MT/ID/WY)
persisting into Monday morning. Snow levels will be around 3500ft
in the Bitterroots and north, around 5000ft in the Sawtooths of ID,
and 5500ft around Yellowstone. Day 1.5 snow probabilities for >6"
are 30-60% through these ranges and over 80% in the Wind River in
WY.


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


Jackson