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FOUS11 KWBC 281947
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
247 PM EST Wed Jan 28 2026

Valid 00Z Thu Jan 29 2026 - 00Z Sun Feb 01 2026


...Great Lakes...
Days 1-3...

The seemingly endless cyclonic flow that has kept the LES machine=20
cranking over snow belts of the Great Lakes looks to continue
through the remainder of the work-week. Frigid 850mb temperatures=20
will persist with temperatures around -18 to -24C, which are below
the 10th climatological percentile. According to GLERL, Lake Erie=20
is effectively ice covered, so available moisture will be limited=20
there while Lakes Superior and Ontario remain largely open. W-NWrly
low-level winds will continue today before the approach of a sharp
500mb shortwave passes through and shifts winds more out of the=20
north by late Thursday. Northerly flow continues Friday with=20
shifting NNE flow possible into Saturday, which could place the=20
Chicagoland area under the presence of a Lake Michigan single-=20
banded LES streamer late Friday into Saturday. 72-hour WPC=20
probabilities depict high chances (>70%) for snowfall totals >8"=20
over the eastern shores of Lake Superior in the Michigan U.P. and=20
down wind of Lake Ontario to the south of an over the Tug Hill. The
area with the best odds of seeing over a foot of additional snow=20
(most on Day 1) over the next few days are near the Oswego, NY area
where WPC probabilities for over a foot of snow are 10-20%. Day 3=20
probabilities down wind of Lake Michigan current depict moderate-=20
to-high chances (40-70%) for at least 4" along the southern shores
of Lake Michigan.


...Cascades & Olympics...
Days 1-3...

A series of storm systems tracking into the Gulf of Alaska will
direct rounds of moisture and WAA at western WA through the
remainder of the week. Strong upslope flow should support locally
heavy snowfall totals as low as 4,000ft, but most heavy snow will=20
reside in the more remote areas above 5,000ft. Snow levels rise=20
from 4000 to 5000ft over the WA Cascades Wednesday through=20
Thursday. By Friday, snow levels approach 6,000ft by Friday in
western WA. WPC probabilities for >4" is moderate (40-60%) around=20
Stevens Pass, but lighter accumulations around Snoqualmie are=20
anticipated at this moment given the higher snow levels.

...Northern & Central Plains...
Days 1-3...

A weak Pacific shortwave trough tracking NW-SE will ride along a
nearby 850mb front to support periods of snow from the northern
High Plains on south in the the central High Plains. Guidance is
even keying in on an area of 700mb FGEN over the Black Hills on
south into the Nebraska Sand Hills that could support moderate snow
bands Friday morning. Snow is not expected to be overly heavy,=20
although the Black Hills through orographic lifting and some=20
localized banding may be able to see snowfall amounts surpass 6".=20
This is supported in WPC probabilities which show moderate-to-high=20
chances (50-70%) for >4" of snow in the Black Hills, and low-to-=20
moderate chances (20-50%) in their peaks for >8". Elsewhere, from=20
eastern MT on south and east through the Missouri River Valley,=20
most snowfall accumulations are likely to range between 1-3". Even=20
some localized instances of freezing rain in the northern High=20
Plains on late Friday into Saturday given the favorable overrunning
from WAA at low-mid levels and sub-freezing surface temps. Some=20
hazardous travel is possible, especially where roads temperatures=20
are at or below freezing in wake of the recent extreme cold.


...Southern Appalachians & Mid-Atlantic...
Days 2.5-3.5...

...Confidence growing for a major winter storm & heavy snowfall=20
across the southern Mid-Atlantic...

WPC cluster analysis continues to show the primary driving factors
in the development of this impending winter storm are the
strength/speed/tilt of the approaching shortwave trough in the
Great Lakes and the spacing between the trough and the TPV over
southeast Canada. The meteorology is supportive of a significant
winter storm from the southern Appalachians and Carolinas on north
and east through the VA Tidewater. Just about all ensemble=20
guidance now show the shortwave trough over the OH Valley Friday=20
evening deepening into a powerful and highly anomalous closed low=20
that tracks into the southern Appalachians Saturday evening. By the
end of this forecast period (00Z Sun) the ECMWF 500mb heights are=20
approaching record low levels over the FL Panhandle for late Jan-=20
early Feb. As the 500mb low approaches, exceptional PVA and WAA=20
over the Mid-Atlantic coast will spawn low pressure along the=20
strengthening coastal front. This aligns well across the 12Z GFS=20
and 06Z ECMWF which show increasing 700mb Q-vector convergence near
the NC Outer Banks that fosters healthy mid-level ascent. This=20
aligns favorably beneath the diffluent left-exit region of a=20
>100kt 500mb jet streak located a the base of the closed 500mb low.
As the 700mb low tracks towards the Cape Fear region Saturday=20
night, the axis of heaviest snowfall will reside on the 700mb low's
northern and western flank.

Where guidance still disagrees is the progression of the storm and
its proximity to the coast. The tilt of the 500mb trough and closed
low plays a key role in this, as it maximizes vertical ascent and=20
draws moisture farther north if the system takes on a negative=20
tilt. The EC-AIFS ensemble mean has been gradually decreasing QPF=20
largely because the negative tilt takes longer to occur and there=20
is less time for the developing 850mb low to tap into moisture off
the Gulf Stream. Most guidance holds off on a negative until=20
Sunday, which is why there is a "gap" in the snowfall from northern
VA on up I-95 to the NYC metro area, but heavy snow becomes=20
possible over southeast New England by Sunday thanks to the region=20
sticking out eastward into the Atlantic. Note the 12Z GEFS, 06Z=20
EPS, and 12Z EC-AIFS ensembles are still showing changes in its=20
mean inside of 72 hours, so exact amounts and the expanse of the=20
snow shield are still likely to change. In addition, unlike the=20
last winter storm, wind will have a more profound impact up and=20
down the Eastern Seaboard. The 00Z ECMWF EFI shows wind speeds that
are topping 0.8 from the MA Capes on south along the NC Coast.=20
These anomalous winds also align with climatologically significant=20
snowfall potential along the coasts, indicating the concern for=20
blizzard conditions in affected coastal areas.=20

CIPS Analogs (GFS-based) continue to suggest this storm's=20
potential ceiling could be exceptional, particularly in the=20
Carolinas. CIPS is keying in on several past major winter storms=20
that featured similar 300mb & 500mb evolutions to what the GFS is=20
showing, just 100-200 miles farther south and east from where those
events unfolded. While the CIPS analogs are analyzing the GFS, the
differences in the GFS versus the ECMWF are not all that different
when it comes to the meteorology involved: powerful closed upper=20
low, healthy upper-level divergence over a strengthening coastal=20
front, and tapping into Atlantic moisture revolving around the=20
closed 700mb low. In summary-- ensembles are beginning to identify
the floor of this winter storm (disruptive winter storm in the=20
southern Mid-Atlantic) but based on some of the analogs, there is a
potentially more significant-ceiling that could be achieved in the
Carolinas should guidance consolidate on a slower and more intense
winter storm. Given it is 72 hours out, there remains some caution
when it comes to expected snowfall totals.

WPC probabilities through Saturday night currently show moderate-
to-high chances (50-80%) for snowfall totals >4" from the NC=20
Piedmont on east to eastern NC and southeast VA. It is worth noting
some higher end solutions are present with low-to-moderate chances
(30-50%) for snowfall totals >8" over central NC through 06Z Sunday.
The Probabilistic Winter Storm Severity Index (WSSI-P) is=20
depicting >50% chances for Moderate Impacts from the SC/GA border=20
on north and east to lower DelMarVa Peninsula. The Major Impacts=20
are >50% in the eastern Charlotte metro, the NC Piedmont right=20
along NC's I-95 corridor, and into southeast VA. These elevated
WSSI-P Major probabilities highlight the concern for a highly=20
impactful winter storm late Saturday and into Sunday for the=20
southern Mid-Atlantic with more disruptions to travel and=20
infrastructure anticipated. Residents and those traveling to the=20
Carolinas on north up the East Coast will want to continue=20
following the forecasts from WPC and your local NWS WFO for the=20
latest regarding this potential winter storm.


The probability for significant icing is less than 10 percent.


Mullinax




...Winter Storm Key Messages are in effect. Please see current=20
 Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=
stKeyMessage_1.png__;!!DZ3fjg!5Cj4msK-dv0Kb7_AGDSgu7ZDdEOXNYFYPw2QvpYtmFd6N=
CNtmp24XMTtrscfs6fvs4sGCn1UXXix-0GDZBAeT4q-EBM$=20

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=
stKeyMessage_2.png__;!!DZ3fjg!5Cj4msK-dv0Kb7_AGDSgu7ZDdEOXNYFYPw2QvpYtmFd6N=
CNtmp24XMTtrscfs6fvs4sGCn1UXXix-0GDZBAeMWJe7mA$=20



$$

=3D =3D =3D
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