Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sat Dec 03 2022

Valid 00Z Sun Dec 04 2022 - 00Z Tue Dec 06 2022

...A cold front ushers in cooler temperatures and drier conditions along
the East Coast...

...Heavy snow in the Sierras and isolated flash flooding possible in the
Southwest...

...Thunderstorms and scattered instances of flash flooding expected Monday
for the Lower Mississippi and Tennessee Valleys...

The large-scale upper level pattern will remain relatively in place over
the next couple of days with a deep, mean low centered over Canada, a
ridge over the Gulf, and a positively-tilted trough over the West Coast.
Southwesterly flow across the CONUS as well as smaller scale impulses
aloft rotating around the mean low will help to drive the surface frontal
pattern and subsequent weather hazards. Lingering rain showers along the
East Coast and a wintry mix in the Interior Northeast will taper off
through Saturday evening as a cold front pushes through off the coast.
Blustery conditions that prompted Wind Advisories for portions of the
Interior Northeast will also continue to wane through this evening. The
cold front will usher in cooler, closer to average early December highs
for Sunday and Monday after a mild Saturday for most. Temperatures will be
in the 30s and 40s for the Northeast and Mid-Atlantic, the 50s for the
Carolinas, and 60s to the south of the front in the Southeast.

In the West, Pacific moisture streaming in with generally southwesterly
flow beneath the trough aloft as a surface frontal system slowly pushes
eastward will help to continue to spread lower elevation/valley rain and
higher elevation snow chances across the region. The heaviest snow will be
in the Sierras where Winter Storm Warnings are in effect through Monday as
total accumulations will measure in the feet. Snow levels will lower in
the presence of cooler air over portions of the northern Great Basin where
1-3 inches of snow are forecast through the day Sunday. Otherwise, most
snow accumulations should be seen mainly in the mountains of the
Northwest, California, and Northern and Central Rockies. An area of
enhanced moisture streaming in from the Pacific over southeastern Arizona
and southwestern New Mexico will help promote locally heavier showers
Monday, and an isolated instance or two of flash flooding is possible.

A cold front will move southward through the Plains on Monday as warm,
moist air from the Gulf will accompany a northward moving warm front into
the Lower Mississippi Valley and Southeast. Showers are forecast ahead of
the cold front over the Lower Great Lakes and Ohio Valley, with
thunderstorms likely for the Lower Mississippi and Tennessee Valleys in
the more buoyant air further south along the warm front. Heavier rainfall
is possible where more widespread, repeated rounds of storms move along
the returning warm front. A Slight Risk (level 2/4) of Excessive Rainfall
is in effect for northern Mississippi, northern Alabama, and northwestern
Georgia along where this boundary is currently forecast to be located, and
scattered instances of flash flooding are possible. Meanwhile, further
north behind the cold front, frigid temperatures will begin to stream into
the Northern and Central Plains. Highs on Monday will be in the teens for
portions of Montana and North Dakota with 20s as far south as northern
Nebraska. Temperatures will feel below zero near the Canadian border with
the wind chill factored in.

Putnam


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