Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
155 PM EDT Fri May 1 2026

Valid 00Z Sat May 02 2026 - 00Z Tue May 05 2026

...Sierra Nevada...
Day 3...

A large mid-level low but with modest amplitude will swing onshore
central California Sunday night into Monday morning, producing
modest height falls across the area. At the same time, downstream
SW flow will transport increasing moisture into the region, with PW
anomalies progged to exceed the 90th percentile according to the
NAEFS ensemble tables. In general, forcing for ascent will
transient outside of upslope enhancement in the Sierra, with
periodic vorticity impulses leading to expanding precipitation.
Snow levels during this time will fall slowly from around 9000ft
to 8000ft, with locally lower snow levels to 7500ft possible at
times in response to briefly enhanced ascent on steep lapse rates
to pull down some colder air. However, the most significant snow
accumulations, which will still be modest at generally 2-4" (WPC
probabilities for more than 4 inches are just 10-30%) will remain
above 9000ft and above most of the passes.


The probability for significant icing over one-tenth of an inch is
less than 10 percent across the CONUS.


Weiss