Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
256 AM EST Tue Dec 26 2023

Valid 12Z Tue Dec 26 2023 - 12Z Thu Dec 28 2023

...Significant winter storm with heavy snow, blizzard conditions, and
potentially damaging icing continues across portions of the north-central
U.S. through early Wednesday...

...Moderate to heavy rain for much of the East as the work week begins,
with potential flooding across portions of the southern and central
Appalachians...

...Precipitation chances pick back up across northern California and the
Pacific Northwest Wednesday...

A large, dynamic storm system over the central U.S. will continue to bring
impactful winter weather to portions of the north-central U.S. through
early Wednesday. Heavy snow continues this morning under a deep upper-low
as a long fetch of moisture moves northward ahead of a cold front pushing
eastward towards the East Coast and wraps back around a surface low over
the central Plains. The snow is expected to continue through Tuesday
evening, gradually tapering off Tuesday night through early Wednesday. The
highest additional totals of around 2-4", locally 8", are expected across
western South Dakota, western Nebraska, far eastern Wyoming, and
northeastern Colorado, with some lighter snow into the Middle Missouri
Valley. There is a high chance (70+%) that storm total snowfall will
exceed a foot for areas of south-central South Dakota and north-central
Nebraska. In addition, strong winds gusting upwards of 55 mph will lead to
blizzard conditions. The combination of heavy snow rates and white-out
conditions will make travel difficult to impossible. A significant
freezing rain event also continues from portions of northern/eastern South
Dakota into southern/eastern North Dakota. Ice accumulations of 0.25 to
0.5", locally 0.75", will lead to potentially significant tree damage and
power outages. A wintry mix will likely follow the surface low track into
the Middle Mississippi Valley Wednesday.

Widespread showers and thunderstorms ahead of the cold front will spread
eastward from the Lower Great Lakes, Upper Ohio Valley, central/southern
Appalachians, and the Carolinas Tuesday into the Mid-Atlantic and New
England by Wednesday. Moderate to locally heavy rainfall is expected.
There is a higher potential for a few inches of rain along upslope
portions of the central/southern Appalachians Tuesday, and a Slight Risk
of Excessive Rainfall (level 2/4) is in effect as some scattered instances
of flash flooding are possible. An isolated instance or two of flash
flooding may also occur Wednesday across the Mid-Atlantic.

Some light lower elevation/coastal rain and higher elevation snow showers
are forecast Tuesday for the Pacific Northwest and into the Northern
Rockies as a Pacific system weakens this morning. Another system will
approach the West Coast early Wednesday with precipitation chances quickly
ramping back up. Moderate to locally heavy rainfall is likely,
particularly for upslope favorable areas along the higher terrain of
northern California where snow levels will be high. Heavy snowfall should
be limited to higher mountain peaks. Some isolated flooding may occur.

High temperatures will remain anomalously warm, upwards of 10-20 degrees
above average, from the Upper Midwest into the Great Lakes and interior
Northeast Tuesday and Wednesday. Many will see highs in the 40s and even
some low 50s. While not quite as anomalous, conditions will also remain
above average along the East Coast, with 50s for the Mid-Atlantic and 60s
in the Carolinas and Southeast. Temperatures will be cooler under the
influence of the upper-low over the central Plains, with mainly 30s and
40s. Highs will be around average from the Lower Mississippi Valley into
Texas with 50s and 60s forecast. The West will also be running a bit above
average, with highs in the 30s and 40s for the Great Basin, 50s and 60s in
the Pacific Northwest and California, and 60s and 70s in the Desert
Southwest. 

Putnam

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