Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
231 AM EST Wed Feb 21 2024

Valid 12Z Wed Feb 21 2024 - 12Z Sat Feb 24 2024

...The West...
Day 1...

A weakening low continues to drift north just off the PacNW coast
today with a shortwave trough zipping across SoCal early this
morning on a 150kt + jet that pushes it across the southern
Rockies this afternoon. Pacific Moisture continues to stream in
over the Southwest ahead of this trough axis with moderate snow
above about 6000ft for all Utah ranges, the Kaibab Plateau north
of the Grand Canyon in AZ, and ranges over northern CO/southern WY
where Day 1 PWPF for >6" are 30-80%. Precip wanes tonight behind
the shortwave trough axis, mainly ending by sunrise Wednesday.
Continued onshore flow east of the low off the PacNW continues to
bring moderate precip with snow levels around 4500ft today along
the Cascades where Day 1 PWPF for >6" is 30-70%. This low weakens
over western WA/Vancouver Island tonight with precip mainly
tapering off this evening.


...Maine...
Day 3...

The shortwave trough approaching southern CA this morning will
continue to sweep east in zonal flow over the southern CONUS
through Thursday night before getting caught in a trough rounding
a deep low centered over eastern portions of Hudson Bay. This
draws the shortwave trough up the Northeastern Seaboard Friday,
allowing a coastal low to develop in/near the Gulf of Maine late
Friday that pushes to the Canadian Maritimes Friday night.
Moisture surging ahead of this low brings likely light rain and
higher elevation snow to the Northeast Friday with the potential
for wrap around bands over much of Maine Friday night. As of now
the Day 3 PWPF for >6" is 10-30% over well interior portions of
Maine, though banding potential late Friday night looks to be best
over Down East Maine in the 00Z GFS/ECMWF.


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


Jackson