Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
258 AM EST Fri Dec 24 2021

Valid 12Z Fri Dec 24 2021 - 12Z Sun Dec 26 2021

...Wet, wintry, windy, and a White Christmas for some in the West with
hazardous travel conditions in mountainous terrain...

...Anomalous, record-breaking warmth will continue to overtake much of the
South...

...Scattered rain showers and a wintry mix forecast along a frontal system
moving across the Great Lakes and Northeast...

The weather for both Christmas Eve and Christmas Day is highlighted by a
stormy upper level troughing pattern along the West Coast and strong upper
level high pressure over the South-Central U.S.. In Christmas-speak, it
means Snow Miser has control of the West while Heat Miser has full control
of the weather in Southtown with no compromise of snow in Southtown this
Christmas. Starting out West, a pair of storm systems are set to produce
measurable snow in the higher elevations of the Intermountain West and
along the West Coast. One disturbance tracking into southern California
this morning is responsible for the snow in the southern and central
Rockies while persistent onshore flow ushers Pacific moisture into the
Northwest today. Snow totals exceeding a foot are expected in the Sierra,
Cascades, and most of the higher elevations of the Rockies today. By
Christmas Day, the Four Corners region dries out, but the next storm
system diving south from the northeast Pacific delivers the next round of
heavy mountain snow and coastal/valley rainfall to the West Coast. By
Christmas night, parts of the Sierra Nevada, Cascades, and Salmon
mountains will measure anywhere from 2 to 4 feet of snow with locally
higher totals possible. Travel will be be hazardous, even impassable at
times, in the hardest hit locations with towering snow drifts and whiteout
conditions. Meanwhile, the immediate West Coast from western Washington to
southern California can anticipate 1 to 2 inches of rain on average today
through Christmas night. The areas most at risk for flooding today are far
southern California and central Arizona where excessive rainfall rates
could lead to areas of flash flooding this morning.

In contrast to the West, those dreaming of a White Christmas throughout
much of the South and East Central U.S. will have to settle for
spring-like temperatures this Christmas. Daytime highs Christmas Eve from
the Middle Mississippi Valley to West Texas are forecast to reach the 70s
and 80s with some locations not only breaking daily record highs, but
potentially challenging December record highs. Christmas Eve night
temperature anomalies will be 25 to 35 degrees above normal from the Ohio
Valley to the Southern Plains with record breaking warm daily minimum
temps likely. Temperatures so mild, that Santa may want to pack a lighter
red coat when going house to house. By Christmas Day, the spring-like
air-mass reaches the Mid-South and Mid-Atlantic with highs in the 60s and
70s. More record warmth is likely, most notably from the Tennessee and
Ohio Valleys to "Deep in the Heart of Texas". Aside from the cooler than
normal conditions on the West Coast, the only other area forecast to
witness below normal temperatures are the High Plains of Montana and North
Dakota. A cold front pushing south through these states will introduce an
injection of frigid Canadian temperatures, causing daily lows to plummet
below zero Christmas morning and high temps struggling to get out of the
single digits Christmas Day.

Elsewhere, Rudolph will need his red nose at full power over the Great
Lakes Christmas Eve night thanks to a storm system producing showers and
overcast conditions. By early Christmas morning, precipitation will fall
in the form of snow and/or a wintry mix in New England. Light snow and ice
accumulations could make for dicey travel conditions on Christmas Day. As
a new area of low pressure forms along a frontal boundary off the
Northeast coast, precipitation may switch over to all snow in northern New
England Christmas night and into early Sunday morning. In the North
Central U.S., a weak area of low pressure is set to trigger show showers
in Northern Plains and Upper Midwest Christmas Eve night and into early
Christmas morning with light snow accumulations possible.

Mullinax


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