Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
256 AM 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...


...Upper Midwest/Great Lakes...
Days 1-3...

Deepening area of low pressure over the U.P. of Michigan will
reach peak intensity today as it moves eastward into Canada.
Northerly flow on its northwest side will continue to wrap in
moisture all the way around from the Northeast US with additional
infusion from Lake Superior. Lake enhanced snow will transition to
lake effect snow over northern WI and the U.P. of Michigan this
afternoon/evening and continue through Thursday and into Friday as
upper troughing will be slow to move out. NW flow across Lake
Michigan will signal the start of lake effect snow into the Lower
Peninsula as well, starting overnight. Lastly, after the cold front
clears through western NYS today, the lake machine will pick up
off of Lakes Erie and Ontario and continue through Friday and into
Saturday morning as additional height falls and PVA flow out of
Ontario across the Great Lakes. Winds will remain blustery to
strong at times (especially along lake shores), creating blowing
and drifting snow. The snow bands off of the eastern lakes will
start as single bands on SW to WSW flow before transitioning to
more multi-bands off at least Lake Erie as the flow veers to W then
WNW and NW on Friday.

Snow will accumulate rapidly under the more intense lake bands
that remain over the same area. The most favored locations for this
will be over the western to central U.P. of Michigan where the
multi- banded flow can still be quite intense. WPC probabilities
for an additional 8 inches of snow after 12Z today are at least 50%
over northern WI, most of the U.P. of Michigan (except for areas
closer to Lake Michigan), northwest Lower Michigan, 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 >50% for 18 inches of snow.
Isolated totals could exceed 30 inches, including what has already
fallen.

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


...Northern Rockies...
Day 1...

Pacific system moving through WA/OR this morning will weaken but
retain its moisture through the northern Rockies. Generally lighter
snow is expected with moderate (30-60%) probabilities of at least
6 inches of snow for parts of the Absarokas and south central MT
ranges.


...Cascades, Northern Rockies/Plains to the Corn Belt...
Days 2-3...

The next Pacific system will approach the coast late tonight with
some light WAA-driven snow to the WA Cascades. Bulk of the
precipitation comes in on Thursday with high snow levels around
5000ft (north) to 7000ft (south), limiting accumulations to the
higher mountains. However, the mid-level shortwave will maintain
its identity as it crosses the Divide and is joined by an incoming
shortwave out of western Canada Friday. This combined longwave
trough will then digs through the Rockies as lee-side surface
cyclogenesis occurs over eastern WY/CO Friday afternoon. 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. WPC probabilities for
at least 8 inches of snow are >50% over the northwestern MT
ranges. Over the valley floors, WPC probabilities for at least 4
inches of snow are generally >50% east of the Divide and including
the Absarokas and Bighorns.

Farther east, north of the developing surface low, sfc-850
troughing and WAA will enhance snow as well over
northern/northeastern MT that will eventually stretch
eastward/southeastward onto the Northern Plains Friday afternoon.
The addition of Gulf moisture from the south will help the snow
quickly expand ESE from the Plains to the Corn Belt by Friday
evening and continue into early Saturday, driven by 850-700 WAA and
surface convergence near/north of the warm front. By early
Saturday, the upper jet will sharpen along 100W and help to
continue to deepen the surface low over the central Plains. Light
to moderate snow will continue across the Corn Belt and become
heavier by the end of this forecast period (to continue into the
medium range). Through 12Z Saturday, WPC probabilities for at least
4 inches of snow are >30% from along the ND/SD border
southeastward through southwestern MN into Iowa. There (northern
Iowa), low chances (10-30%) of at least 6 inches of snow are shown
with more to come.


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

Fracasso


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

Ongoing storm:

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

Next system:

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