Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
345 AM EDT Sat Apr 30 2022

Valid 12Z Sat Apr 30 2022 - 12Z Tue May 03 2022

...Pacific Northwest to the Central Plains...
Days 1-3...

A closed mid-level low and its associated frontal system are
forecast to move into Oregon this afternoon, bringing a
combination of rain and high elevation snow to the region. Apart
from the high peaks of the Olympics, Cascades, Blues, and ranges
in central Idaho, significant snow accumulations are not expected.
On Day 2, the system will drop southeastward through the Great
Basin into the central Rockies, with any snowfall over a few
inches confined to the Uintas and Wind River Range. By Day 3, as
the system moves east of the central Rockies into the High Plains,
model spread remains rather high on how the surface system
develops off the Front Range. Some of the modest including the NAM
and GFS were quite aggressive with rain changing to snow Monday
morning into the afternoon over the Nebraska Panhandle. Though the
conditions in the deformation band just to the NW of the 700/850mb
lows may support local cooling of the column and a wet snow,
timing would be during the day and fighting May sun angle. WPC
probabilities for at least 4 inches of snow are less than 10
percent but some snow could accumulate given stronger rates.

Also on Day 3, yet another closed low is forecast to move into the
Pacific Northwest with high elevation snow to the Oregon Cascades
and again to the Blue Mountains and central Idaho ranges.

The probability of significant icing is less than 10 percent.

Fracasso