Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
315 PM EDT Fri Apr 26 2024

Valid 00Z Sat Apr 27 2024 - 00Z Tue Apr 30 2024

...Great Basin into the Rockies...
Days 1-2...

A mid-level shortwave and upper jet will continue to carve out an
anomalously deep trough over the Southwest, with a closed low
developing over the Four Corners tomorrow. This will bring
widespread high-elevation snow from the Sierra to the Rockies, with
locally heavy accumulations expected.

Areas more likely to be impacted by heavy accumulations include the
western Wyoming ranges. Easterly winds sandwiched between a mid-level
low moving through Utah and high pressure over Montana will
combine with favorable upper forcing to support heavy snow this
evening into the overnight, especially along the Wind River Range
(above 9000 ft). WPC PWPF shows 50 percent or greater probabilities
for accumulations of a foot or more along the favored terrain.

The central Rockies, from the Medicine Bow Mountains south along
the Front Range, will likely be impacted as well. As a mid-level
center develops over eastern Colorado, upslope flow along with
left-exit region upper jet forcing will support heavy snow across
the region beginning overnight and continuing into late Saturday.
For areas above 8000 ft, probabilities for accumulations of a foot
or more are above 50 percent.

...Pacific Northwest...
Day 3...

While unsettled weather is expected across the region through the
period, an upper-level shortwave associated with a low sliding
southeast from the Gulf of Alaska and the northeastern Pacific will
move across the region on Monday, driving snow levels down and
increasing the coverage of accumulating snows across the Olympics
and Cascades. This includes the Cascades passes, where WPC PWPF
indicates that at least a few inches of snow can be expected on
Monday.

The probability of significant icing is less than 10 percent.

Pereira