Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
404 PM EDT Thu Nov 02 2023

Valid 00Z Fri Nov 03 2023 - 00Z Mon Nov 06 2023

...Northern Rockies...
Day 1...
The forecast remains on track for 6-12" (locally higher) atop
elevated portions of the Absarokas, as remnant atmospheric river
moisture migrates into the interior Northwest and interacts with
transient right entrance forcing over the Northern Plains. As the
main plume of moisture exits east, zonal upslope flow should
maintain snowfall over the Northern Rockies through tomorrow
before rising heights result in a brief lull in mountain snowfall
Friday afternoon.


Day 3...
Onshore flow resumes early Saturday as another atmospheric river
approaches the Northwest within a strong Pacific jet, with PWATs
1-2 sigma above climatology noted across the region by Saturday
evening per the latest NAEFS guidance. By 0z Monday, recent PWPF
depicts a 50-60% chance for 4" atop the Absarokas, with a more
muted signal (30%) for 4" also depicted over small portions of the
Salmon River Mountains and Cascades.  

The probability of significant icing is less than 10%.


Asherman