Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sun Jan 19 2025

Valid 00Z Mon Jan 20 2025 - 00Z Wed Jan 22 2025

...Winter storm to bring moderate to locally heavy snow to the interior
Mid-Atlantic and Northeast through tonight...

...A reinforcing surge of frigid air will bring dangerously cold
conditions to much of the nation...

...Impacts from a rare, significant winter storm across the South next
week will begin for southern Texas Monday night spreading east to the
central Gulf Coast region on Tuesday...

...A Critical Risk of Fire Weather returns for southern California
Monday...

A low pressure system currently developing and beginning to exit the
Mid-Atlantic states will continue to bring the latest round of wintry
weather from the interior sections of the eastern U.S. up across New
England through tonight into Monday morning.   The heaviest snow will
likely stay to the north and west of the I-95 corridor.  Milder air from
the nearby Atlantic will keep the precipitation in form of rain/drizzle
this afternoon for the eastern portion of the Mid-Atlantic states before
colder air in the wake of the intensifying low pressure system changes the
rain to a period of snow this evening.  As the intensifying cyclone tracks
just off the New England coast tonight, a swath of snow is forecast to
overspread southern New England into coastal Maine where 3-6 inches of
accumulation with locally higher amounts can be expected.  Meanwhile, rain
is expected near the Cape Cod area and east end of Long Island before
changing to a period of snow as the deepening storm begins to move away
later tonight.  Partly sunny skies will return on Monday for much of the
East Coast.  However, blustery northwesterly winds behind the storm will
usher in the coldest arctic air this season, bringing tumbling wind chills
and below freezing temperatures all the way down to the Gulf Coast,
Florida Panhandle and northern Florida by Monday morning behind an arctic
front.  In addition, this expansive frigid air mass will continue to
trigger the latest round of heavy lake-effect snow along the Snow Belt of
the Great Lakes with cold northwesterly flow firmly in place.  Sub-zero
temperatures will be common across the northern U.S. through the next
couple of mornings with readings approaching -30 degrees near International
Falls.  Cold Weather Watches/Warnings and Freeze Warnings are in effect
all the way down to the Gulf Coast including southern Texas and northern
Florida.

Over the central/southern Rockies and adjacent High Plains, some snow
showers will return on Monday as a shortwave dips into the region in the
presence of post-frontal upslope flow.  This shortwave will be
instrumental in producing a very rare winter weather event across the Deep
South beginning Monday night, and even down along the Gulf Coast on
Tuesday.  As the shortwave begins to interact with the arctic front
lifting north across the Gulf of Mexico, a low pressure system will
intensify and track eastward and dump Gulf moisture into the cold air for
the Gulf Coast states.  This will result in very rare and significant
snowfall accumulations with preliminary estimates upwards of 5 inches just
inland from southeastern Texas across southern Louisiana on Tuesday.  A
few inches of snow is also possible near the New Orleans metropolitan area
by Tuesday evening.  In addition, a period of ice is possible near the
immediate coast of Texas into Louisiana.  Given the rarity of this winter
storm, major traffic and travel disruptions are likely through mid-week.

Some of the arctic airmass will reach portions of the Great Basin/Interior
West as well, with highs by Tuesday only recovering into the 20s and 30s
for most locations. Forecast highs are generally milder and around average
along the West Coast, with 40s for the Pacific Northwest, the 50s and 60s
for California, and the 60s to low 70s for the Desert Southwest. 
Unfortunately, these mild conditions along with gusty winds and very low
humidity have prompted the Storm Prediction Center to issue a Critical to
Extreme Risk of Fire Weather for southern California for the next few
days.

Kong


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