Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
406 PM EDT Fri Apr 29 2022

Valid 00Z Sat Apr 30 2022 - 00Z Tue May 03 2022


...Pacific Northwest to the Central Plains...
Days 1-3...
A closed low and its associated frontal system are forecast to
move from the eastern Pacific into the Pacific Northwest, bringing
a combination of rain and high elevation snow to the region
beginning tonight and continuing into Saturday.  Apart from the
high peaks of the Olympics, Cascades, and Blues, significant snow
accumulations are not expected.  This system is expected to drop
southeast into the Great Basin on Sunday, with the bulk of the
guidance indicating little to no threat for widespread heavy
snowfall accumulations through Sunday.  However, as the system
moves east of the central Rockies into the High Plains, model
spread increases, with some models including the GFS and NAM quite
bullish with rain changing to snow, with possibly heavy
accumulations developing within the associated deformation zone
centered over the Nebraska Panhandle and southwestern South Dakota
on Monday.  While the GFS and NAM are quite heavy, the latest WPC
probabilities for significant accumulations are quite low.

Meanwhile, a second closed low is forecast to move into the
Pacific Northwest, bringing another round of high elevation snows
to the region on Monday.  

The probability of significant icing is less than 10 percent.

Pereira