Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
323 AM EDT Sat Nov 1 2025

Valid 12Z Sat Nov 01 2025 - 12Z Tue Nov 04 2025

...Washington Cascades...
Days 1 & 3...

A longwave trough entrenched over the northeast Pacific will direct
a continuous fetch of Pacific moisture and embedded storm systems
at the Pacific Northwest and British Columbia over the next 5-7
days. For the purposes of this short range discussion, Days 1 and 3
pose some threat for locally heavy snowfall in the Washington
Cascades. While there will be sufficient QPF throughout the Pacific
Northwest (>1,000 kg/m/s IVT today), the lack of a continental
polar air-mass is forcing heavier snowfall to accumulate above
4,000ft. Some lighter accumulations are possible around Stevens
Pass (1-3" through Sunday AM), most accumulating snowfall will
reside above pass level through Sunday AM. By Monday and into early
Tuesday, another Pacific storm system will approach the coast of
Oregon, but there remains a high degree of uncertainty as to how
far north the QPF reaches and how far inland it advances. At the
moment, WPC probabilities show low chances (10-30%) for snowfall
totals >4" on Monday. But cumulatively through this weekend and on
Monday, WPC probabilities show moderate-to-high chances (50-80%)
for snowfall >8" above 5,000ft. There were low-to-moderate chance
probabilities (30-50%) for snowfall >4" over the next few days at
Stevens Pass.


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

Mullinax