Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sat Jan 18 2025

Valid 00Z Sun Jan 19 2025 - 00Z Tue Jan 21 2025

...Winter storm to bring moderate to heavy snow to the Mid-Atlantic and
Northeast on Sunday...

...Accumulating snowfall across the central Rockies to adjacent
central/southern High Plains will redevelop on Monday...

...More arctic air intrusion will bring very cold to dangerously cold
conditions into much of the nation...

Over the next couple of days, arctic air will continue to engulf much of
the mainland U.S. under the influence of an expansive high pressure
system.  As the arctic air pushes farther south toward the Gulf Coast,
moisture being lifted northward from the Gulf of Mexico will interact with
a frontal boundary where a low pressure system is forecast to intensify
and track across the Deep South into the Southeast tonight, and then
through the Mid-Atlantic states on Sunday.  An expanding swath of wintry
precipitation can be expected well north of the cyclone track while
rain/showers and embedded thunderstorms will be farther south across the
Southeast including Florida.  In terms of wintry precipitation, snow is
expected to be the main precipitation type from interior Mid-Atlantic into
much of the Appalachians, the upper Ohio Valley on Sunday, and through the
Northeast Sunday night into Monday morning.  The heaviest snow is forecast
just to the north and west of the I-95 corridor where 3 to upwards of 8
inches with locally higher amounts can be expected as far west as West
Virginia, and as far north as Downeast Maine by the time the intensifying
cyclone exits into the Canadian Maritimes during the day on Monday. 
Blustery north to northwesterly winds behind the big storm will usher the
expansive pool of arctic air across the Great Lakes and into the entire
East Coast on Monday, triggering a new round of heavy lake-effect snow for
the Snow Belt downwind of the lower Great Lakes.  Lake-effect snow will
intensify downwind from the upper Great Lakes through the remainder of the
weekend into Monday.  Meanwhile, showers and thunderstorms can become
quite strong as they traverse northern Florida into southern Georgia
tonight into Sunday morning ahead of a cold front.

On the other side of the front, moisture moving downstream from upslope
flow forced by the plunging arctic high pressure system from western
Canada will promote additional accumulating snowfall from the central
Rockies into the central High Plains including the Texas Panhandle.  It
appears that the snow will taper off on Sunday before the next surge of
arctic air triggers another round of snow showers first over the northern
Rockies Sunday night, before spreading southeast and expanding into the
central Rockies and nearby High Plains on Monday.

Besides the wintry weather, dangerously cold temperatures spreading across
much of the Lower 48 this weekend and into next week will be the other big
weather story.  Sub-zero low temperatures will engulf much of the northern
U.S. by Monday morning.  Forecast highs will range from below zero to the
single digits in the northern Plains/Upper Midwest, the teens and 20s
across the central Plains and Midwest.  Meanwhile, sub-freezing
temperatures will penetrate down to the Gulf Coast by Monday morning with
only southern Texas and a good portion of Florida staying above freezing. 
Plunging wind chills will be ushered into the East Coast on Monday behind
the cyclone.  Meanwhile, dangerously cold wind chills of 30-55 degrees
below zero are expected across the Rockies, northern Plains, and Upper
Midwest Sunday and continuing into next week. This will pose a
life-threatening risk of hypothermia and frostbite to exposed skin. Wind
chills below zero will reach as far south as Oklahoma and the Tennessee
Valleys. Temperatures will remain near average west of the Rockies, with
30s and 40s for the Interior West/Pacific Northwest, the 50s and 60s in
California, and the 60s and 70s in the Desert Southwest.

Kong

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