Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EST Fri Dec 29 2023

Valid 12Z Fri Dec 29 2023 - 12Z Sun Dec 31 2023

...Pacific storm system brings locally heavy rain to California Friday;
moderate to heavy snow forecast for the Sierras Saturday...

...Wintry mix expected for the Interior Northeast/New England, with some
accumulating ice and snow in Maine...

...Above average temperatures forecast for most of the country Friday and
Saturday; cooler temperatures and chilly morning lows for the Southeast...

A Pacific storm system will approach the West Coast Friday morning,
bringing increasing precipitation chances to California and the Pacific
Northwest. Moderate to locally heavy rainfall is likely for much of
California Friday, focusing along the northern and central coast and along
the higher terrain of the coastal ranges. Snow levels will start rather
high as a plume of warm, moist air moves in from the Pacific, keeping
snowfall limited to higher mountain peaks. Areal average rainfall totals
of 1-3" may lead to some isolated flooding concerns. Some gusty winds are
also expected. Precipitation totals will come down some Saturday as the
system weakens, but spread a bit further inland, with a light wintry mix
for western portions of the Great Basin. Also, as snow levels come down
with cooler air moving in, some heavier snowfall totals between 8-12" will
be possible for the Sierra, locally as high as 1-2 feet. Most of the
precipitation should come to an end by later Saturday night, early Sunday
morning. 

To the east, a frontal system dropping southward from Canada into the
Interior Northeast/New England will bring a wintry mix Friday, starting
out as rain for many locations before transitioning to snow by Friday
night into Saturday. Any snow accumulations should remain limited.
However, one exception will be in interior Maine where freezing rain
accretions of 0.1-0.2" and snowfall of 1-2" may be a bit more disruptive
to any travel this holiday weekend. A very light wintry mix will also
likely continue to linger Friday further south and west into the Ohio,
Tennessee, and Middle Mississippi Valleys as well as the central and
southern Appalachians under the influence of a deep upper low. Some light,
spotty showers will also be possible in the Mid-Atlantic and northeastward
through coastal New England. Precipitation chances Saturday should remain
light and be limited to the Appalachians and New England. Elsewhere, a
clipper system passing through the Upper Midwest/Great Lakes Saturday may
bring a few light snow showers. The rest of the country looks to remain
dry. 

Most of the country will see high temperatures running above average
Friday and Saturday. Conditions will be most anomalous Friday from the
Northern Plains into the Upper Midwest/Great Lakes where highs in the 30s
and 40s are 15-20 degrees above average. Temperatures will drop into the
20s and 30s Saturday. Elsewhere, forecast highs range from the 30s and 40s
in New England, the 40s and 50s for the Mid-Atlantic, the 40s and 50s for
the Central Plains, and the 50s and 60s for the Southern Plains/Texas. In
the West, 30s and 40s are expected for the Rockies/Great Basin, with 50s
and 60s for the Pacific Northwest and California and some 70s into the
Desert Southwest. One area where temperatures will be running below
average is from the Lower Mississippi Valley into the Southeast, as
conditions will be slower to moderate following a cold front passage and a
deep upper low passes overhead. Forecast highs are mainly in the 40s and
50s, with some chilly morning lows dropping to at/near freezing along the
central/northern Gulf Coast.

Putnam


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