Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
358 AM EST Fri Jan 23 2026
Valid 12Z Fri Jan 23 2026 - 12Z Mon Jan 26 2026
...Major winter storm to bring the potential for crippling icing,
significant sleet, and heavy snow from the Southern Plains through
the Southeast and up the Atlantic Coast into New England...
Forecast remains largely on track with only minor changes compared
to the previous cycle, with typical uncertainties surrounding the
depth and northern push of the mid-level warm nose. While this
uncertainty is rather minor from a synoptic scale, local forecasts
can still be drastically impacted by this feature. The event will
begin this morning across the Southern Plains and expand towards
the MS VLY tonight. The driver of this winter storm is an
impressive overlap of intensifying synoptic ascent with increasing
subtropical moisture.
The synoptic pattern becomes favorable today in response to the
evolution of multiple shortwaves rotating through an amplifying
trough across the eastern CONUS. A closed 500mb low off the Baja
Peninsula will begin to open and shear to the east, at the same
time dual shortwaves dig out of Saskatchewan/Alberta and into the
Northern Plains. As the northern shortwaves dive south and the Baja
low ejects east, the interaction of these features will lead to
increasing mid-level divergence overlapping pronounced height falls
to produce rich deep layer lift. The northern shortwave has
trended a tad slower with overnight guidance and allows for more
ridging out ahead of this system, helping shift the mid-level warm
nose farther north. Regardless, the impressive ascent will be on
top of an arctic cold front that will be sagging southward into the
Southern Plains and eventually work its way southeast to the Gulf
and Atlantic coasts by Saturday. This overlapping ascent will
materialize atop a moistening column as subtropical moisture
downstream of the Baja low streams northeast reflected by IVT that
reaches above the 97th percentile according to NAEFS, in a broad
swath from Texas to the Carolinas, with above the record (CFSR at
00Z) climatology by Sunday evening in the east.
This increasing moisture will result in a large swath of
precipitation expanding from the Southern Plains today, to the
MS VLY and TN VLY Saturday, into the Carolinas and Mid- Atlantic
by Sunday, and finally reaching the Northeast Sunday night. This is
a very large and impactful system across a huge portion of this
country. While impacts will be considerable in many areas (aided by
extreme cold), the icing (and sleet) and snow will be most
impressive across two distinct areas.
Freezing Rain and Sleet:
Arguably the most lasting impact associated with this winter storm
could be from heavy accumulating freezing rain and sleet stretching
from the Southern Plains, Mid- South, Tennessee Valley, and
southern Mid-Atlantic. This is due to very cold low-level arctic
air being reinforced by the strong high over the north-central U.S.
(and enhanced by pronounced mid-level confluence over the Great
Lakes and New England) and a warm nose aloft (at around 750mb per
cross section model soundings) melting snow as it falls through the
column before refreezing just before or at the surface,and in some
places this re-freezing layer is above the 90th percentile in
terms of depth, suggesting some locations will experience
exceptional sleet accumulations.
The greatest freezing rain amounts and impacts are currently
forecast across northeast TX through northern MS as favorable
thermal profiles linger for over 24 hours beginning Friday night.
WPC 72-hour probabilities for >0.5" of freezing rain are high >70%
across southern AR/northern LA into parts of northern MS. Here,
ice accretion could be crippling and exceed 0.75-1.00", (WPC
probabilities 40-50% for 1" of ice) which would almost certainly
lead to widespread long-lasting damage to infrastructure, including
power outages and tree damage. Major sleet accumulations are also
likely just north of the freezing rain area stretching from
southern OK/north TX through central AR and into the Mid- South,
with more than a few inches of sleet possible. The consistency of
the guidance in both placement and amounts for this area are
resulting in high confidence in an extreme event, leading to long-
lasting impacts both to travel and infrastructure due to the
bitterly cold airmass expected to linger into next week over the
region.
Heavy icing is also expected farther east into the southern
Appalachians and southern Mid-Atlantic. The setup across the
southern Mid- Atlantic down as far south as northern GA and areas
just inland from the coasts of the Carolinas is an extreme case of
CAD with a 1040mb high situated over the Interior Northeast on
Saturday night. While regional soundings indicate there may be
considerable sleet in this area as well, especially across southern
VA into northern NC, these CADs are notorious for their effective
dry/isallobaric flow, enhanced by precipitation, leading to dry
wet-bulb advection offsetting the latent heat of freezing during
freezing rain. With such an impressive high in place at
precipitation onset, this will likely result in considerable
accumulations of sleet and freezing rain here, too, with WPC
probabilities indicating a moderate-to-high risk (60-80%) of at
least 0.5", highest across the Piedmont and northern GA. The
guidance has trended just a bit colder this afternoon, but
significant icing is also possible as far north as Richmond, VA and
towards southern MD.
Heavy Snow:
North of the mixed precipitation area and closely tied to both a
favorable LFQ of a zonally oriented 180kt upper jet and strong
700mb fgen, snow is the primary precipitation type stretching from
the southern High Plains of east-central NM and the southern
Rockies through the Plains, Mid-Mississippi Valley, Ohio Valley,
Mid-Atlantic, and reaching the Northeast by Sunday evening (with
additional expansion beyond this forecast period).
Favorable upslope flow as the strong arctic high pressure noses
southward along the High Plains behind a strong cold front starts
on Friday across the southern Rockies, with light snow and even a
chance for freezing drizzle at onset across the central Plains
until the column fully saturates. Heavy snow is then forecast to
begin breaking out Friday night from the central/southern Plains
through the mid-Mississippi Valley and spanning much of the Ohio
Valley and parts of the Midwest on Saturday. Snowfall rates could
near 1"/hr as strong lift through WAA/fgen intersects with a
region where the DGZ is forecast to be extremely deep (SREF
probabilities above 70% for >100mb of depth). This would allow for
efficient formation of dendrites where ample lift can fully
moisture the column. While this depth is impressive, regional
forecast soundings indicate that the best ascent may lie below this
DGZ in many areas, and there is only modest indication of any
isothermal layer beneath the DGZ to maintain aggregates. Despite
this, efficient and fluffy SLRs are likely in this area, and with a
long duration event expected, WPC probabilities are moderate
(40-60% )for at least 12 inches from southeastern KS and
northeastern OK into southern MO, with widespread 4+ inches
extending all the way back into the TX Panhandle and lower MS VLY.
Trends have been more favorable for snow vs lately on D1 across
eastern OK and central AR as guidance depicts stronger mid-level
fgen and dynamic cooling aloft to keep the entire column below 0C.
00z HREF also depicts the potential for 1"/hr snowfall rates in
this region. Will monitor this for potential adjustments
downstream.
Farther east, some heavier snowfall is becoming more likely for
parts of the Ohio Valley, and into the Mid-Atlantic, and especially
Northeast. Here, pronounced WAA and accompanying 850-700mb fgen
will drive pronounced ascent into a rapidly moistening column
thanks to IVT above the 90th climatological percentile. As the
upper trough (interaction of the southern and northern streams)
deepens over the Plains, downstream ascent will maximize and a
period of impressive WAA snow with snowfall rates >1"/hr are
likely. As secondary low pressure develops offshore (in a Miller B
type evolution), banded structures within the WAA are likely to
translate northward from the Mid-Atlantic into New England, and
then may pivot and drift eastward Sunday night into Monday. Where
this occurs, the heaviest total snowfall accumulations are
probable, reflected by WPC probabilities that are already above 60%
for 12+ inches. While there is some uncertainty into how much
mixing will pivot northward, especially from Washington D.C.
through Long Island, the interior portions (NW of I-95 and into
southern New England which will remain cold as the secondary low
develops and tracks near the 40/70 Benchmark) will remain mostly
snow with above- climo SLRs leading to significant snowfall
accumulations. One other uncertainty that has creeped into the
forecast is a pesky dry slot moving into the Mid-Atlantic and
Northeast Sunday night. This could dry out the mid-level and
drastically cut both precipitation and SLRs. In fact, freezing
drizzle could develop early Monday morning from northern Va to
northern NJ in this scenario before stronger westerly flow picks
up on Monday. Many areas are expected to receive more than 12
inches from the Ohio Valley through the Mid- Atlantic and into the
Northeast before this system winds down in New England on Monday
/D4/.
Key Messages for this system are linked below (Key Message 2)
...Great Lakes...
Day 1...
Expansive mid-level low centered over the Hudson Bay will begin to
shear open and translate to the east today as a secondary
shortwave rotates through its base and atop the Great Lakes this
evening. Behind this impulse, shortwave ridging will amplify
across the area, bringing an end to the persistent CAA and
associated lake- induced ascent on D1.
The subsequent W/NW flow and accompanying CAA will lead to
impressive lake effect snow (LES) in the favored W/NW snow belts
D1, with some pivoting to more N/NW by early Saturday. The
heaviest snowfall is likely east of Lake Ontario D1 where WPC
probabilities indicate a moderate risk (50-70%) for at least 8
additional inches in the Tug Hill Plateau. Elsewhere, WPC
probabilities suggest a moderate risk (50-70%) for at least 6
additional inches across the northeastern U.P.
Additionally, as an arctic cold front pivots into the Northeast,
snow squalls along and behind this front are possible. For more
details on the snow squall threat in the Northeast through Friday,
please refer to our Key Messages (Key Messages 3) below.
Snell/Weiss
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