Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
335 AM EST Mon Feb 19 2024

Valid 12Z Mon Feb 19 2024 - 12Z Thu Feb 22 2024

...California and The West...
...Particularly heavy snow continues this morning on the Sierra
Nevada above about 7000ft...

Days 1-3...

Deep low pressure off the far northern CA coast slowly weakens as
it drifts north off the PacNW coast through Tuesday. Ample onshore
moisture continues to stream inland as a slowly backing powerful
jet streak (WSWly becoming SWly) pushes into SoCal with the left
exit region providing lift over the Sierra Nevada where
exceptional hourly snow rates of 3-5"/hr continue above about
7000ft until about 18Z today. Travel is become difficult to
impossible on the higher Sierra passes. Pivoting trailing
shortwave on the backside of the mean trough axis will allow for a
continued moisture flux into the region until its passage Tuesday
night. Day 1 (after 12Z today) PWPF for over 18" is 70-95% for the
crest of the Sierra Nevada and the Shasta-Siskiyou. Day 2 PWPF for
>8" is 40-80% over the same terrain as well as SoCal ranges over
about 7000ft.

Across the Great Basin, moisture will continue to advect inland on
SW flow aloft, favoring the higher ranges in NV through tonight
and the Wasatch and Unitas tonight through Wednesday, then into
the southern WY/CO Rockies Tuesday night until the trough axis
crosses the southern Rockies late Wednesday. WPC probabilities for
at least 8 inches of snow peak are moderate to high for Utah
ranges on both Day 1.5 and 2.5 and starting on Day 2.5 for
Colorado.


The probability of receiving at least 0.1" of ice is less than 10
percent Day 1-3.


Jackson