Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
302 AM EST Mon Jan 29 2024

Valid 12Z Mon Jan 29 2024 - 12Z Thu Feb 01 2024

...Southern and Central Appalachians...
Day 2...

A Canadian clipper system associated with a closed mid-level low
will dive southward out of the Great Lakes on Tuesday, with a
brief moisture surge into the central/southern Appalachians.
Generally light snow is expected as it quickly moves through, but
some favored higher elevations could squeeze out a few inches. WPC
probabilities for at least 4 inches of snow are low -- generally
less than 20% and confined to mountain tops.


...California...
Day 3...

A strong Pacific jet will nose into SoCal midweek, with a closed
mid-level low well northeast of the Pac NW and a strong cold front
to its east. Ahead of the front will likely be a significant plume
of moisture -- NAEFS IVT already at the 99th percentile as it
pushes ashore NorCal Wednesday then continues southeastward.
Antecedent conditions have been quite warm, and snow levels will
start high around 7000ft at precipitation onset. By 12Z Thursday,
snow levels will start to fall, especially west of 120W, as colder
air moves in behind the front. This will drop snow levels down to
around 5000ft in the Klamath Mountains before pushing into the
northern Sierra thereafter. WPC probabilities for at least 6
inches of snowfall are greater than 50% above 7000ft over NorCal
and into part of the Sierra, with much more snow to follow into
D4.


The probability of significant icing greater than 0.10" is less
than 10% for days 1-3.


Fracasso