Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Fri Oct 17 2025

Valid 12Z Fri Oct 17 2025 - 12Z Mon Oct 20 2025

...Northern Rockies...
Day 1...

A 125kt jet along 50N into southwestern BC will dip down across
the US/Canadian border as mid-level height falls push into western
MT late this afternoon and overnight. A surface cold front will
move quickly through the region with NW flow in its wake,
supporting a broader area of light snow and some enhanced upslope-
driven snow for the MT Absarokas and into the Bighorns. WPC
probabilities of at least 4 inches of snow are about 20-60% above
8000-9000ft.

...Pacific Northwest and Northern Rockies...
Days 2-3...

A buckled upper jet will move into the Pacific Northwest early
Sunday, with a cold front and attendant atmospheric river of
moisture aimed into the region from the southwest. High snow levels
above 7000ft early Sunday (coincident with the heavier
precipitation) will lower to just under 5000ft Sunday
afternoon/evening as heights reach their lowest point in the fast
flow. Snow will quickly spread from the WA Cascades eastward to the
northern Rockies (western MT/Idaho into northwestern WY) as the
cold front races eastward. WPC probabilities for at least 8 inches
of snow days 2-3 are >50% above about 5000ft over the WA Cascades
and around 6500ft in northwestern MT.

The probability of significant freezing rain across CONUS is less
than 10 percent.


Fracasso