Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
431 PM EDT Sat Oct 10 2020

Valid 00Z Sun Oct 11 2020 - 00Z Wed Oct 14 2020

Days 1-3...

...Pacific Northwest to the Northern Rockies...
A strong trough moving through the PacNW this afternoon will
continue to push a cold front through the northern Rockies and
northern Great Basin into Sunday. In the wake of the trough axis
is a strong and deep zonal flow into the northwest Sunday through
Tuesday. Shortwave troughs in the zonal flow reach Vancouver
Island Sunday afternoon and late Monday night, providing two
additional waves of precip with mountain snows through Tuesday.

Snow levels have dropped to around 5000ft for the WA/OR Cascades
behind this cold front. Snow levels will also drop to around
5000ft tonight across the northern Rockies before a general warm
up/snow level rise to 6000 to 8000ft in the zonal flow Sunday
night persisting through Monday/Tuesday.

Heavy snow is expected at times tonight higher elevations from the
WA Cascades to the Rockies north from northern WY where there are
moderate probabilities for 6 or more inches on Day 1. The
subsequent shortwaves are pretty contained to near the US/Canada
border, so the associated heavy snow is limited to The WA Cascades
and northern ID/western MT Rockies on Monday/Day 2 where there are
moderate probabilities for 6 or more inches on on Day 2. Day
3/Tuesday is even farther north with some low to moderate
probabilities for 6 or more inches are limited to the northern WA
Cascades and terrain for ID/MT along the Canadian border.


The probability of significant icing is less than 10 percent.

Jackson