FOUS11 KWBC 242013
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
313 PM EST Sat Jan 24 2026

Valid 00Z Sun Jan 25 2026 - 00Z Wed Jan 28 2026

...Ongoing major winter storm to bring crippling icing,
significant sleet, and heavy snow from the Southern Rockies/Plains
through the Southeast and up the Atlantic Coast into New England...

Meteorological Overview...
Forecast remains on track as a massive winter storm, set to
produce a swath of heavy snow, significant sleet, and dangerous ice accumulations, continues across the Southern Plains and begins to
expand into the Ohio and Tennessee Valleys this afternoon. By
tonight, wintry precipitation is expected to lift into the Mid-
Atlantic, and reach New England on Sunday. By the time this event
winds down late Monday, it will leave a trail of more than 2000
miles of wintry precipitation, in a nearly continuous path, from
New Mexico to Maine.

The driver of this event will be the interaction of a northern
stream trough diving out of Canada with a southern stream impulse
ejecting from near Baja California. As these features move eastward
through the weekend and interact into a more amplified and larger
trough over the eastern CONUS, impressive subtropical moisture
will spread east/northeast both from the Pacific and the Gulf, with
IVT exceeding the 97th climatological percentile according to
NAEFS. The rich moisture from the south will accompany strong
850-700mb WAA that results in classic over-runing along an area of
850-700mb FGEN stretching from atop the Southern Plains to the TN
VLY and southern Mid-Atlantic by tonight, reaching New England
Sunday, and then finally exiting the Atlantic Coast on Monday. In
addition to the classic overrunning/WAA precipitation, the
placement of the upper jet as it strengthens and pivots poleward,
will support intense bands of snowfall (cross sections suggest a
high threat for CSI and even potential CI within the strongest WAA)
which will support snowfall rates of 1-2+"/hr at times where it is
all snow, and intense sleet/freezing rain rates in mixed zones.

Farther to the east, an intense CAD (Cold Air Damming) signature
will develop east of the Appalachians, with intense dewpoint
depressions of 20-30F during precipitation overrunning. While it
will take a while to saturate this to result in precipitation at
the surface, the intensity of this high with cold isallobaric
drainage aided both by mid-level confluence to the north and
precipitation falling into this wedge will enhance the CAD and
result in long duration mixed precipitation as the WAA pushes a
warm nose aloft (generally 800-700mb). This will support heavy
icing and sleet lifting northward into the Mid-Atlantic on Sunday,
and potentially as far as the south coast of New England as well.

With intense IVT pushing PWs to above the 99th percentile, there
will be plentiful moisture to work with everywhere from Texas
through New England. This will support heavy precipitation
accumulations regardless of p-type, so substantial impacts are
expected for a large swath of the nation. The heaviest snow is
expected from the Ohio Valley into the Northeast (more outlined
below), but an impressive jet-forced band of snow is also likely
from the Texas Panhandle through the Mid-Mississippi Valley.
Farther south, crippling icing is expected for parts of
AR/LA/MS/TN, as well as the Carolinas, with exceptional sleet
accumulations of several inches progged in between the snow and ice
from Arkansas through Kentucky, and then for portions of the Mid-
Atlantic as well.\

Heavy Snow/Sleet...
Snow will be winding down across the Southern Plains after 00Z
this evening (the start of the forecast period) but remain across
NM and of course farther east into AR/MO. This still supports an
astonishingly long swath of >6" of snowfall from NM to ME.

From the Southern Plains through the Ohio Valley, 72-hr WPC
probabilities (so the entire forecast period although snowfall
should generally be a 24-hr period, a heavy band of snowfall on the
NW side of the low and within the strengthening jet streak will
support 1+"/hr snowfall as reflected by the WPC prototype snowband
tool. With this band likely translating along its long axis, heavy
snowfall will have a temporal extent sufficient for more than 8
inches (30-50% chance from the TX Panhandle through SW MO,
increasing to 90%+ in the Ohio Valley where more than 12 inches is
also likely (50-70% chance) before snow wanes from SW to NE on
Sunday. Locally 15+ inches is possible across southern OH.

The heaviest snow is likely from Pennsylvania through New England
where p-type changes are not likely. This is also where the longest
duration of heavy snowfall within both WAA banded structures and
then potentially a more pivoting/translating band will develop as
secondary low pressure skirts off the Mid-Atlantic coast and just
inside the Benchmark (40N/70W). This will support a longer
duration of 1-2+"/hr snowfall, and WPC 72-hr probabilities reach
above 70% for 12+ inches, and locally as much as 2 feet is possible
(especially in the Worcester Hills, Berkshires, and Catskills, as
well north of Boston along the coastal front) where WPC
probabilities for 24" are 10-30%. However, this will be a
widespread 12+" snowfall event for most of southern and central New
England as well as PA.

In addition, with the intense WAA, a warm nose aloft (generally
800-700mb) will gradually create a warm nose above 0C shifting
through the Mid-Atlantic, with additional warm nose/sleet impacts
expected from AR and into TN and KY. The cold depth below this warm
nose appears to be in many places above the 75th-90th percentile
for freezing rain, indicating primary sleet for these areas as
p-type transition occurs, with significant sleet accumulations of multiple-inches expected. This will result in tremendous impacts to
travel in these areas.

The WSSI shows widespread Major Impacts (considerable disruptions
to daily life: dangerous to impossible driving conditions,
widespread closures, and disruptions to infrastructure) from the TX
Panhandle on east to the Ozarks, through the OH Valley, and all the
way to New England. Every major market along the I-95 metropolitan
corridor (Washington D.C. to Boston and even as far north as
Portland, ME) are expecting major impacts due to snow. The
D.C/Baltimore area on north to Philly and NYC are likely to see
some inclusion of sleet, but it will still result in significant
impacts when accounting for heavy snowfall that is expected to
exceed warning criteria (5-6"). A reminder that bitterly cold
temperatures will follow in wake of this storm through the middle
of next week throughout the eastern U.S., so snow/sleet impacts
will linger for many days even after precipitation ends.

Freezing Rain...
The most lasting impact will come as a result of significant to
locally catastrophic ice accumulations due to prolonged periods of
freezing rain. Just like the swath of >6" of snowfall, the areal
coverage of high chances (>50%) in WPC's ice probabilities
exceeding one-quarter inch of ice accumulation is expansive from
eastern TX through southern KY, with a secondary area east of the
Cumberland Gap from northern GA through southeast VA and including
much of the Carolinas. In these regions, at least 0.25" of ice is
expected to be widespread, with a more narrow corridor embedded
within of at least 0.5" (50-90%), highest in northern MS and
western TN, but some higher potential also exists in GA/SC where
locally more than 1 inch (a catastrophic accumulation for damage
and prolonged impacts of a week or more) is possible (10-30% chance).

For LA, MS, TN, this ice accumulation is "additional" beyond what
will occur before 00Z (6pm CST), so local amounts above 1" are
actually expected to be more widespread than the updated
probabilities suggest. This produces a 20-40% chance of Extreme
impacts (extensive and widespread disruptions to infrastructure)
and these impacts could linger for a week or more where icing is
most significant. With very cold weather in place, this will become
a life-threatening situation, with potentially impossible travel
due to downed trees and power lines.

Key Messages for this system are linked below (Key Message 2).
Key messages for the widespread extreme cold are linked below as
well (Key Message 1).

...Great Lakes... Day 3...

Broad cyclonic flow will persist across the east, but an embedded
shortwave within this trough will dig out of Alberta Monday night
and then cross the Great Lakes from northwest to southeast during
Tuesday. This will enhance CAA, leading to another round of lake
effect snow (LES), although the duration and intensity of this
event should be modest overall, some moderate accumulations are
still expected beginning D3 /00Z Tuesday to 00Z Wednesday/ and
lingering beyond this forecast period. LES from Lake Erie should be
minimal as that lake is now ice covered according to GLERL, but
elsewhere, WPC probabilities are moderate for 4+ inches near the
Tug Hill Plateau, and moderate (10-50%)for 2+ inches along the
western shore of the L.P. of MI as well as parts of the U.P.


Snell/Weiss

...Winter Storm Key Messages are in effect. Please see current
Key Messages below...

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_2.png

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