Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 PM EDT Mon Oct 21 2024

Valid 00Z Tue Oct 22 2024 - 00Z Fri Oct 25 2024

...Glacier National Park...
Day 1...

Shortwave trough ejecting eastward across the Northern Rockies will
drive a cold front east into the High Plains overnight. W/NW mid-
level flow in the wake of this feature will advect modest moisture
into the Northern Rockies, although PW anomalies will gradually
erode from near +1 sigma to start the period to nearly -1 sigma by
Tuesday evening. This will result in a gradual wane in snowfall,
although the westerly upslope flow into the residual elevated 700mb
RH will allow for at least periods of moderate snow to persist at
least the first half of D1. Total accumulations will be modest,
however, although WPC probabilities for more than 6 inches reach as
high as 50% in a few of the higher terrain features of Glacier NP.
Additionally, some light snow accumulations around 1" or so are
possible at Marias Pass making for some early season hazardous
travel.

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

Weiss