Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
339 PM EST Sun Jan 01 2023

Valid 00Z Mon Jan 02 2023 - 00Z Wed Jan 04 2023

...Winter storm forecast to bring heavy, blowing snow and freezing rain to
the Central Plains and Upper Midwest...

...Flash flooding and severe weather expected for the South...

...Precipitation chances continue across the West as unsettled weather
pattern remains in place...

The main weather story to start the new year continues to be with the
impacts related to a storm system currently moving through the Rockies and
forecast to intensify after it reaches the Plains, with a winter storm,
flash flooding, and severe weather all expected. Divergence aloft ahead of
an eastward moving upper-level trough will help to enhance a deepening low
pressure center, with a warm front pushing northward over the South and
Midwest as a cold front pushes eastward over the Southern Plains and into
the Lower Mississippi Valley. A winter storm will start to ramp up later
Sunday night in the colder air to the north and west of the surface low
track across the Central Plains and eventually into the Upper Midwest with
numerous winter weather-related advisories in effect. There is still
lingering uncertainty as to the exact surface low track and frontal
features which will determine the distribution of precipitation types and
amounts. Currently, the axis of highest snow amounts of 6-12", locally
higher, stretches from eastern Wyoming northeast through northwestern
Nebraska, southern South Dakota, southern Minnesota, and northwestern
Wisconsin. The axis of freezing rain will track just to the southeast of
the heavy snow axis, with the most significant ice accumulations of
greater than 0.25" currently expected for northwestern Iowa and southern
Minnesota. Vigilance to the most recent forecast is important given the
potential for heavy snow rates of 1-2"/hr and blowing snow, leading to
significant travel impacts, and with the highest accumulations of freezing
rain potentially leading to power outages. Colder temperatures will flow
southward from Canada to the west of the low, with highs in the teens and
20s expected in the Northern Plains Monday and highs falling into the 30s
and 40s for the Central Plains and portions of the Southern Plains
Tuesday.

A broad warm sector will also develop ahead of the surface low track/cold
front as the warm front lifts northward into the Midwest. Widespread
thunderstorms will develop along and ahead of the cold front as enhanced
lift from divergence in the upper-level jet aloft overspreads a very moist
and unstable airmass moving northward from the Gulf. Anomalously high
moisture will lead to the potential for very heavy downpours. There is a
Slight Risk of Excessive Rainfall (level 2/4) for portions of the Southern
Plains into the Lower/Middle Mississippi Valley Monday and for portions of
the Tennessee Valley as well as the Florida Panhandle on Tuesday as the
system continues east. Areal average rainfall totals upwards of 2", with
locally higher amounts of 3-4", may lead to scattered instances of flash
flooding. In addition, increasing speed and directional shear both aloft
and in the low levels, along with sufficient CAPE, will lead to the threat
of severe weather. The Storm Prediction Center has issued an Enhanced Risk
(level 3/5) of severe weather centered on the ArkLaTex where damaging
winds, large hail, and tornadoes will all be possible, including the risk
for strong tornadoes. There is a Slight Risk (level 2/5) for portions of
the Lower Mississippi to Tennessee Valley on Tuesday for the continued
threat of damaging winds and a few tornadoes. 

Meanwhile, in the West, higher elevation mountain snow and a lower
elevation/valley wintry mix will linger over the Great Basin,
Central/Southern Rockies, and Southwest through Monday before the storm
system pushes further out into the Plains. Additional snow accumulations
of 12"+ are forecast in the various mountain ranges across the region,
with storm total snowfall in the Wasatch potentially reaching upwards of
3-5 feet. Snow levels will continue to fall as a cold front pushes through
the region late this evening and many of the lower elevation/valley areas
that have seen rain will transition over to snow outside of the Desert
Southwest. Given how long these areas have remained rain, only light
accumulations of snow are expected. After a break in the wet weather for
the West Coast for New Year's Day, precipitation chances will ramp up
again Monday and Tuesday as a series of Pacific Storm systems continues to
impact the region. Less Pacific moisture is expected over the next couple
of days as compared to this past week's system, so rainfall amounts should
be lighter with no flood-related impacts currently anticipated. Mountain
snow looks to be limited to higher elevations of the Sierras and Northern
Coastal Ranges in California. High temperatures will remain 10-20 degrees
below average given the upper-level trough aloft and unsettled pattern
continuing. Highs in the 20s and 30s are forecast for the Interior
Mountain West, with 40s and 50s for the Pacific Northwest, California, and
the Desert Southwest. 

Temperatures will remain well above average to the east of the storm
system by upwards of 20-30 degrees for early January. Widespread highs in
the 60s are forecast for portions of the Lower Great Lakes, Ohio Valley,
and Mid-Atlantic, with 70s for the Southeast and Carolinas. With high
pressure in place, conditions will also be tranquil for the East Coast
Monday and most of Tuesday before showers and thunderstorms ahead of the
approaching system move in later Tuesday night.

Putnam

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