Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
445 AM EDT Mon Oct 09 2023

Valid 12Z Mon Oct 09 2023 - 12Z Thu Oct 12 2023

For Days 1-2, the probability of significant snow or ice
accumulation across the contiguous U.S. is less than 10 percent.

...Day 3...
Northern Rockies...

A mid-upper level trough will move from the Pacific Northwest
Tuesday night to the central/northern Rockies by Wednesday night.
Meanwhile, a near 110-kt jet positions itself across Nevada/Utah,
putting portions of the Intermountain West to Northern Rockies in
the favored left-exit region. A front crossing the region will
bring colder air with 700 mb temperatures falling below 0C,
lowering snow levels initially from 9000+ ft to around 7000-7500
ft. By early Thursday, as the core of the upper low settles over
the region, the colder temps combined with a lingering surface
trough will enhance precipitation, particularly across portions of
WY. WPC probabilities for Day 3 (12Z Wed-12Z Thu) for at least 4
inches are between 10-40 percent for portions of the Colorado
Rockies, the Utah Unitas, and portions of the Snake River region
and southwest Montana mountains. Probabilities for at least 4
inches are highest (40-70+ percent) for western Wyoming ranges
including Tetons, Wind River, and the Big Horns with the greatest
probabilities above 8500-9000 ft where probabilities for at least
8 inches are 10-20 percent.

Taylor