Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
214 PM EDT Wed Apr 30 2025

Valid 00Z Thu May 01 2025 - 00Z Sun May 04 2025


...Central/Southern Rockies...
Days 1-2...

Cold front associated with a shortwave over the Northern Plains to
the central Rockies will continue southeastward through Colorado
and into New Mexico Thursday. QPF has decreased in the past 24
hours but some light snow over the high mountains will fall,
generally above 8000-9000ft, where WPC probabilities for at least 4
inches of snow are >50% above 10,000ft or so. Snow will end from
north to south over the San Juans and Sangre de Cristos Thursday
evening.

...Sierra Nevada...
Days 1&3...

Combination of a small upper low off the central/southern CA coast
tonight into Thursday with a trough axis across the Great Basin
will bring some light snow to the high Sierra tonight/Thursday.
Amounts may only be an inch or two with low probabilities of at
least 4 inches (<40%) as snow levels remain above 9000ft.

After a break on Day 2, a deeper trough with origins in the
northeastern Pacific will bring in a more robust moisture plume to
the West Coast on Day 3 (Saturday) that will continue into the
medium range. Through 00Z Sun, snow levels will be high (>9000ft)
with the initial surge in (modest) moisture, yielding low
probabilities for at least 4 inches of snow (<30%) in the central
Sierra as well as across the highest peaks of the Oregon Cascades.


The probability of significant freezing rain across the CONUS is
less than 10%.

Fracasso