Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
336 AM EST Tue Jan 11 2022

Valid 12Z Tue Jan 11 2022 - 12Z Fri Jan 14 2022

...Pacific Northwest into Northern Rockies...
Days 1/2...

The second shortwave in a rapid series moving into BC will track
over the Queen Charlotte Sound late today with an associated warm
front stalling over western/southern WA into Wednesday. Pronounced
Pacific moisture streaming ahead of a stronger shortwave or low
reaching western WA Wednesday night will converge on this front
tonight and promote high elevation heavy snow for the WA Cascades
as snow levels lift above 8000ft. Day 1 snow probabilities for
more than 8 inches are moderately high for the WA Cascades across
to the northern tip of ID. Moisture and low level forcing quickly
lifts into BC Wednesday and with a weakening/progressive wave on
Thursday, little additional snowfall is expected after tonight.

At the same time, continued cold air over the Columbia Basin and
periods of light precipitation spilling over the Cascade crest
will allow for light freezing rain accumulations to occur into
Wednesday with Day 1 WPC ice probabilities for more than a tenth
inch are 40 to 80%.


...Great Lakes...
Days 1-3...

The next cold front settles across the northern portions of the
lakes Wednesday with the trailing high pressure center tracking
along Lake Superior's Ontario shore Wednesday afternoon making for
a brief period of LES for the U.P. and a bit more precip in
westerly low level flow above a sfc cold front that settles over
Lake Ontario and brings some LES to the Tug Hill. Day 2 snow
probabilities are moderately high for more than 4 inches there
with marginal thermals being the main limiting factor (so higher
elevations in the Tug Hill will help produce snow). An upper
trough/trailing sfc high then tracks toward the Great Lakes
through Thursday night with some low (around 5 percent) Day 3 snow
probabilities over the U.P. and Bayfield area of northern WI.

Jackson