Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
215 PM EDT Thu Apr 9 2026

Valid 00Z Fri Apr 10 2026 - 00Z Mon Apr 13 2026


...Sierra Nevada...
Days 2-3...

A lead upper low will weaken into an open wave tonight as it moves
inland over NorCal. Quick on its heels, a more robust closed low
will drop from the Gulf of Alaska on Friday and move into NorCal
Saturday night into Sunday. The lead wave will have some initial
moisture with it, but it will be the second, stronger system that
will be the primary driver for snowfall over the Sierra from late
Friday/early Saturday through Sunday. While moisture/IVT anomalies
will only be modestly high (90th-95th percentile), the slow-moving
nature of the upper low will allow for a longer sustained fetch
into the Sierra. Moderate to heavy snow is expected over the High
Sierra at first, then lowering through many passes as colder air
filters in. Snow levels at precip onset tonight will be above
9000ft but fall to 7500-8000ft Friday morning, 6000ft Saturday
morning, and 4000-4500ft Sunday morning. The heaviest snow is
expected Saturday afternoon through early Sunday morning with
rates of 1-3"/hr.

WPC probabilities for >8 of snow are >50% above 5000ft or so and
for >12" are >50% above 6000-7000ft or so. Total snowfall could
exceed 2-3ft for the event in the higher peaks (>50% chance).
Travel across the higher mountain passes (including I-80) will
increasingly become a concern through the weekend as snow levels
lower. Minor to moderate impacts can be expected over the Sierra
per the WSSI, with isolated major impacts in the High Sierra.

The probability of significant icing for days 1-3 across the CONUS
is less than 10 percent.

Fracasso/Miller