365
FOUS11 KWBC 262025
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
325 PM EST Wed Nov 26 2025

Valid 12Z Wed Nov 26 2025 - 12Z Sat Nov 29 2025


...Significant winter storm with localized blizzard conditions will
continue to impact parts of the Upper Midwest/Great Lakes through
Wednesday as lake effect snow intensifies into Thanksgiving and
Friday for the eastern Great Lakes...

...Confidence increasing on a second winter storm to affect the
Northern Plains Friday and the Midwest/Great Lakes Friday night
into Sunday...


...Key Messages for both systems are in effect and linked below...


...Great Lakes...
Days 1-2...

Strong surface cyclone, 991mb over the central U.P. of Michigan
this afternoon has a well- defined axis of deformation situated
over western portions of Lake Superior down through Wisconsin.
Peak cyclone intensity is now with a gradual occlusion phase
expected as it shifts east tonight. Powerful north to northwest
flow will continue to spread in behind the system making for
prolific lake effect snow (LES). This remains downwind of Lake
Superior through the overnight period with heavy snowfall
situated across all of the Michigan U.P. and the heaviest focused
across the the area from Ironwood over to Marquette. Lake effect
snows will increase over western lower Michigan through this
evening as WSWly flow veers to WNWly and increasing cold air
advection. General persistence in the flow coupled with multiple
shortwave perturbations moving around the periphery of the ULL
positioned over the U.P. and adjacent Ontario will maintain to a
multi- band structure downwind of Lake Michigan. Strongest bands
will likely reside off northern Lake Michigan down through Traverse
City with hi-res CAMs and Canadian Regional highlighting heavy
narrow banding (nearly single banding) from Lake Superior and
northern Lake Michigan fetch to the area northwest of Gaylord
through Thursday night. LES threat diminishes Friday as the flow
decreases with the low approaches the Gulf of St. Lawrence.

Downstream of the eastern Lakes of Erie and Ontario, persistent
LES pattern will ensue this evening behind the swift moving cold
front with snow formation across both lakes by midnight.
Prevailing southwest flow off Lake Erie will kick off the banding
along the southern periphery of the Lake up through the eastern
regions before manifesting into a more consolidated band structure
as it drifts south overnight. Winds will veer more out of the west
and northwest by Thursday afternoon with the banding positioning
becoming more pronounced off the southern periphery of Erie leading
to several inches of snow falling in the adjacent terrain downwind
of the Lake. Lake Ontario will see a similar pattern with
southwesterly flow veering back west in a similar time scale. This
will lead to areas of the Tug Hill and places downwind of the Lake
off I-81 seeing the initial heavy LES signature, eventually with
the banding shifting towards the southeast side of Lake Ontario.
Initial indications are for a long- fetch connection between Huron
and Ontario could enhance banding downwind of the lake on Friday
leading to several inches of snowfall across the southern portions
of the Tug Hill and points south and west.

WPC probabilities for an additional 8 inches of snow after 00Z
Thursday are at least 50% over much of the U.P. of Michigan (except
for areas closer to Lake Michigan), northwest Lower Michigan, far-
northeastern Ohio, northwestern PA, southwestern NY, and around the
Tug Hill Plateau. Within these regions, there is a smaller but still
significant area of probabilities between 40-70% for 18 inches of
snow. Isolated totals could exceed 30 inches, including what has
already fallen across the Michigan U.P. Best chances are likely over
the western U.P. terrain, areas downwind of Lake Michigan and
Traverse Bay, I-90 corridor along the southern lake shores of Erie,
and the Tug Hill down through Oswego county in western New York
state.

Travel will be difficult and perhaps impossible at times due to snow-
covered roads, blowing snow, and low visibility.

Kleebauer/Jackson


...Northwest to Montana...
Days 1-2...

Developed low arrives to the WA Coast early Thursday with elevated
snow levels dropping to around 5000ft in the Cascades through the
day Thursday. Day 1.5 snow probs for >8" are 30-60% for the higher
WA Cascades.

An approaching shortwave trough descends Alberta Thursday night
and meets this low over ID/western MT on Friday. This combined
trough expands over the northern Rockies on Friday, promoting
downstream lee-side cyclogenesis near the eastern WY/CO border
Friday morning. 1040mb+ surface high pressure following from Canada
will help support some lower- level upslope-enhanced snow over
western MT where snow could be heavy at times over the Lewis Range
around Glacier NP particularly Thursday night. Day 2 WPC
probabilities for >8" snow are 50 to 80% over the northwestern MT
ranges down to the Bitterroots.

The arrival of Arctic air Thursday night allows snow for the
valleys/Plains of northern MT through Friday. Banding intensifies
north of the developing surface low with sfc-850 troughing and WAA
enhancing rates across northern MT through Friday morning with
lighter snows for the rest of the state into Friday evening. Day 2
snow probs for >6" are 20-50% over north-central MT.


...Northern Plains through the Midwest...
Days 2/3...

A low level frontogenetical band will set up along the baroclinic
zone northeast of the developing low Friday. Expect moderate to
locally heavy snow to establish in an ever expanding swath of snow
across southwest ND and much of SD Friday, reaching central Iowa by
Friday evening. 3-6" snowfall can be generally expected through
this band with locally higher amounts possible given slow motion
away from its orientation allowing some prolonged snowfall.

By early Saturday, the upper trough will push onto the High Plains,
the surface low is well developed over southern KS with an inverted
trough extending northeast to Wisconsin. Broad cyclonic flow around
this trough with Gulf- sourced moisture allows for rapid expansion
to the precip shield Friday night/Saturday with ample cold air for
snow both on the WAA ahead of the low/ and through the entire back
side/comma head. Broad coverage of moderate to heavy snow develops
Friday night over eastern SD/southern MN/northern IA with expansion
east to lower Michigan then through Saturday. A strong pressure
gradient will make for blustery conditions. Probabilities for
notable snow continue to increase with current Day 3 WPC snow probs
for >8" 40-75% over southern MN down through central Iowa with a
contour of 40% >6" snow from far eastern SD clipping northeast Neb
and including much of northern IL, southwestern WI, and up to the
Twin Cities in MN.



The probability of significant ice across the CONUS is less than
10 percent.

Jackson


...Winter Storm Key Messages are linked below...

Lake Effect Snow:

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

Northern Plains through Midwest System Friday-Sunday:

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



$$