Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sat Dec 31 2022

Valid 00Z Sun Jan 01 2023 - 00Z Tue Jan 03 2023

...Heavy mountain snow and a lower elevation wintry mix for the West...

...Flash flooding and severe weather possible from the Southern Plains to
Lower Mississippi Valley on Monday...

...Winter storm heading for the Central Plains on Monday...

...Pleasant start to the New Year on the East Coast with tranquil
conditions and above-average temperatures...

A significant storm system moving through the Great Basin/Rockies and out
into the Plains and Mississippi Valley will lead to the threat of snow,
flash flooding, and severe weather to start the new year. An upper-level
trough currently along the West Coast will move over the Great Basin,
Rockies, and eventually over the Plains. At the surface, a low pressure
system will move in turn bringing Pacific moisture eastward into the West.
Heavy mountain snow and lower elevation rain currently over portions of
California and the Great Basin this Saturday afternoon will continue into
the Central/Southern Rockies and Southwest on New Year's Day. Numerous
Winter Storm Warnings are in effect for many of the regions mountain
ranges where 12"+ of snow is forecast. Snow levels will be relatively high
initially before falling as a cold front passes through the region. Thus,
precipitation in many lower-elevation valley areas will start as rain
before transitioning to a wintry-mix/snow, and accumulations should remain
on the lighter side. Some more moderate accumulations of 3-6" will be
possible for portions of the Central Rockies where the air will be colder
and the precipitation will be mainly snow. Temperatures will tend to be
10-20 degrees below average throughout the region as colder air settles in
behind the system. Most interior locations will see highs in the 30s, with
40s and 50s for the West Coast and 50s and 60s for southern California and
the Desert Southwest. Another storm system approaching the West Coast
later Monday will bring additional precipitation chances.

As heights begin to fall over the High Plains ahead of the approaching
upper-level trough, the surface low pressure system will be enhanced by
lee cyclogenesis as the system moves out onto the Plains leading to
widespread precipitation chances and hazardous weather across the heart of
the country. Showers and thunderstorms are forecast across portions of the
Central/Southern Plains, Mississippi Valley, and into the Midwest and
Southeast in a broad warm sector ahead of a cold front. There is a Slight
Risk of Excessive Rainfall (level 2/4) for portions of the Southern Plains
and Lower Mississippi Valley as anomalously high moisture flowing
northward from the Gulf will help to increase instability and fuel heavy
downpours, leading to the risk for some flash flooding. This threat will
continue into Monday night and Tuesday morning, just beyond the current
forecast period. In addition, strong wind fields will increase low-level
and deep-layer shear and, with sufficient instability in place, lead to
the risk for severe weather. The Storm Prediction Center has issued an
Enhanced Risk (level 3/5) of severe weather centered over the ArkLaTex
where damaging winds and tornadoes will be possible.

Moderate to heavy snow are also expected Monday in the colder air to the
north and west of the surface low track across the Central Plains. Winter
Storm Watches are in effect from eastern Wyoming into northern Nebraska
and southern South Dakota for storm total accumulations of 6"+, locally up
to a foot in some locations. Some breezy winds could also lead to a few
areas of blowing snow.
A moderate glaze of freezing rain around 0.1" will be possible to the
southeast of the snow axis, most likely from central Nebraska northeast
into northwestern Iowa and southwestern Minnesota.

After a dreary New Year's Eve for much of the East Coast, conditions
should improve Sunday as the rain moves out and temperatures remain above
average. Highs will be in the 40s and 50s for New England and the northern
Mid-Atlantic, the 60s for the southern Mid-Atlantic, and the 70s for the
Southeast.

Putnam

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