Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
234 AM EST Tue Nov 22 2022

Valid 12Z Tue Nov 22 2022 - 12Z Thu Nov 24 2022

...Rain/snow spreads from Pacific Northwest to Northern/Central Plains...

...Temperatures remain below average across Southern Plains;
Northern/Central Plains, Midwest and West Coast warm up...

...Heavy rain potential for Southern Plains and Lower Mississippi Valley
on Thanksgiving...


The upper pattern will go from relatively zonal today to more amplified by
Thanksgiving. A shortwave trough currently in the eastern Pacific will
enter the Pacific Northwest today. This feature will bring low elevation
rain and mountain snow to the region today then the Northern Rockies
tonight before spreading what's left of its moisture over the
Northern/Central Plains on Wednesday. Today's snowfall will occur
primarily over the northern Cascades where 8-12 inches of snow and
isolated higher amounts are expected. Around 0.1 inches of freezing rain
and some sleet are likely to accumulate over portions of east-central
Washington this afternoon. The forecasted precipitation will provide some
relief to parts of the Northwest that have been dealing with poor air
quality.

The shortwave is then expected to dig/amplify down through the Rockies and
into the Southwest/Southern Plains on Wednesday and Thanksgiving. Models
are unusually uncertain with respect to this feature's evolution after
Wednesday, but there's a signal for this amplifying trough to begin
tapping moisture from the Gulf of Mexico and spreading it over the
Southern Plains and Lower Mississippi Valley beginning Wednesday night.
Scattered thunderstorms and moderate to heavy rainfall are possible over
eastern portions of the Southern Plains and much of the Lower Mississippi
Valley on Thanksgiving.

Thermally, the amplifying trough over the Rockies should allow warm air to
advect into the Northern/Central Plains and Midwest today and Wednesday.
An upper ridge will amplify over the eastern Pacific and West Coast, which
will support additional warming for this area through the end of the work
week. Parts of northern California and the Cascades may experience high
temperatures in the 50s and 60s which will constitute a 15-20 degree
positive departure from normal. Elsewhere, a quasi-stationary front draped
across southern Florida will be the focus for scattered to isolated
thunderstorms for the peninsula over the next few days.


Kebede

Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php