Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
313 AM EDT Fri Apr 25 2025

Valid 12Z Fri Apr 25 2025 - 12Z Mon Apr 28 2025


...Sierra Nevada...
Days 1-2...

Positively-tilted trough approaching the central/northern CA coasts
will provide some onshore flow and High Sierra snow today as
initial height falls cross the mountains with snow levels 7000ft or
higher. Slight southward trend continues in upper low track that
reaches the central CA coast Saturday with downstream light to
occasionally moderate snow for the Sierra through Saturday evening
as snow levels lower to around 5000ft. By Sunday, the upper low
will cross through the Great Basin, with Sierra snow ending from
west to east. Day 2 WPC probabilities for >6" are 20-30% in the
5500-6500ft range and 30-60% above 6500ft or so.


...Great Basin and Northern Rockies...
Day 3...

The upper low that crosses the Central CA Coast Saturday pivots
northeast from southern NV to central WY Sunday through Sunday
night. Left exit jet dynamics aid lift ahead of the low where
sufficient moisture is present for valley rain and mountain snow
with snow levels around 6500ft. Day 3 snow is most likely over the
NV ranges, northern Wasatch, with Sunday night snow bands
developing over the Absarokas where there's potential for brief
bursts of heavy snow.


The probability of at least 0.10" of freezing rain across CONUS is
less than 10%.


Jackson