Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
314 AM EDT Tue May 03 2022

Valid 12Z Tue May 03 2022 - 12Z Fri May 06 2022

...Northern to the Central Rockies...
Days 1-2...
A compact but deep closed low at 500mb will move through
southeastern Idaho this morning into Colorado by the end of Day 1.
700mb low over central/eastern Idaho into Wyoming will drop into
eastern Colorado, helping to bring a modest/heavy round of snow to
southern central Montana this morning. Heaviest amounts are
expected to center from the central Idaho ranges into southwestern
Montana and northwestern Wyoming, with additional snow for
northeastern Nevada where moisture wraps back around from the
north into the Independence Mountains. From the the higher
elevations of the central Idaho ranges, including the Lemhi and
Bitterroots eastward to the Absarokas, more than six inches are
likely with measurable accumulations to the high valley floors.
Light to modest snow is expected over the Bighorns southward into
Colorado but some measurable snow is also possible to the valley
floors that are not shadowed. This will continue into Day 2, with
two-day totals over six inches for higher elevations above 7000ft
into the central Rockies.


...Pacific Northwest...
Day 3...
Nose of a 130kt jet will move into WA/OR with a plume of moisture
into the region ahead of a surface front. Snow levels will start
fairly high, resulting in several inches of snow for on the higher
mountain peaks in the Olympics and Washington Cascades.


For days 1-3, the probability of significant icing is less than 10
percent.

Fracasso