Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
419 PM EDT Mon May 02 2022

Valid 00Z Tue May 03 2022 - 00Z Fri May 06 2022

...Northern to the Central Rockies...
Days 1-2...
A vigorous upper level shortwave anchored by a developing closed
low will continue to move east from the Pacific Northwest tonight.
 This will bring lowering snow levels and the potential for heavy
snow into portions of the northern Rockies and the northern Great
Basin beginning tonight and continuing into tomorrow.  Heaviest
amounts are expected to center from the central Idaho into the
southwestern Montana and northwestern Wyoming ranges, where a
700mb low overlapped by left-exit region upper level jet forcing
are expected to help enhance rates.  From the the Sawtooth and
southern Salmon River ranges to the Absaroka, WPC probabilities
indicate that widespread accumulations of 4 inches or more are
likely by late tomorrow.  Heavier accumulations of 8 inches or
more are most likely across the higher elevations of the central
Idaho ranges, inching the Sawtooth and Lemhi. Locally heavy
amounts are also possible farther south across the southern Idaho
to northeastern Nevada mountains.  As the system continues farther
east, high elevation heavy amounts are expected from the Wind
River to the southeastern Wyoming and north-central Colorado
ranges late tomorrow into early Wednesday.  By late Wednesday
however, decreasing moisture in the cold sector will result in
lesser potential for additional heavy snows.

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

Pereira