FOUS11 KWBC 100646
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
246 AM EDT Fri Apr 10 2026

Valid 12Z Fri Apr 10 2026 - 12Z Mon Apr 13 2026

...Sierra Nevada... Days 1-3...

An upper low just offshore NorCal this morning will will weaken
into an open wave this afternoon as it moves inland into the Great
Basin. Moisture is already flowing into the region but temperatures
are mild and snow levels are quite high (>9000ft). Just upstream,
a more robust closed low will drop southward from the Gulf of
Alaska and move into NorCal Saturday night through Sunday and
slowly weaken into Monday. This second stronger system will be the
primary driver for snowfall over the Sierra starting tonight and
continuing through the weekend. While moisture/IVT anomalies will
be modestly high (90th-98th percentile), the slow-moving nature of
the upper low will allow for a longer sustained fetch into the
Sierra at a fairly favorable wind direction from the SW. Moderate
to heavy snow is expected over the High Sierra at first, then
lowering through many passes as colder air filters in. Snow levels
above 9000ft will fall to 7500-8000ft today, 6000ft Saturday
morning, and 4000-4500ft Sunday morning before rising a bit later
in the day into early Monday (5000-5500ft) as the upper low starts
to weaken. The heaviest snow is expected late Saturday afternoon in
northern areas through Sunday across the rest of the Sierra with
rates of 1-3"/hr per the hires CAMS and WPC snowband probability
tracker page.

WPC probabilities for >8" of snow are >50% above 5000-5500ft or so
and for >18" are >50% above 6000-7000ft or so. Total snowfall for
the event could reach 2ft in the higher peaks above 8000ft (>50%
chance) and 4ft in the High Sierra peaks. Travel across the higher
mountain passes (including I-80) will increasingly become a concern
through the weekend as snow levels lower. Moderate to Major level
impacts can be expected over the Sierra per the WSSI.

Snow will also expand across the Great Basin on Sunday with minor
accumulations for most areas. However, parts of southeastern OR,
northern NV, the central ID ranges, and the Wind River Range in WY
could see in excess of 8 inches of snow through 12Z Mon (40-70% chance).

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

Fracasso


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