FOUS11 KWBC 160704
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
304 AM EDT Mon Mar 16 2026

Valid 12Z Mon Mar 16 2026 - 12Z Thu Mar 19 2026

...Upper Midwest through the Great Lakes... Days 1-3...

...Historic blizzard continues today...

The historic blizzard which has been plaguing the Northern Plains
and Upper Midwest will continue in earnest today across the Great
Lakes. The strong surface low driving this impressive event will
steadily advect northeast today after a brief stall this morning
over Michigan during occlusion, leading to continued heavy snow
from northern IL through the U.P. of MI. The low is expected to
pull away well into Canada by 12Z/Tuesday, bringing a slow end to
the blizzard.

The heaviest additional snowfall is expected from southern WI
through the U.P. of MI where snowfall rates above 1"/hr may (60-80%
chance) continue through evening, with the heaviest snowfall
expected in the higher terrain of the U.P. near the Huron
Mountains. The most widespread heavy synoptic snow will wane after
00Z/Tuesday, but before this occurs, the combination of these
intense snowfall rates and gusty winds of up to 50 mph will
continue blizzard conditions. The heaviest snowfall swath D1 is
likely within the impressive deformation axis which will be
pivoting west of the surface low as it lifts north, and this
deformation is progged to dig as far south as IL/IA Monday morning.
This will bring periods of heavy snow and gusty winds with near-
blizzard conditions even south of the heaviest snow. However,
WPC probabilities indicate the heaviest snow is likely for northern
WI, including the Door Peninsula, into the U.P. of MI where they
reach 50-90% for an additional 6+ inches of snow today, with
locally more than 12 inches possible across the U.P. thanks to lake
effect snow contribution (more on that below).

The ongoing key messages for this historic blizzard remain, and are
linked below (Key Message 1).

As the low pulls away late D1 into D2, the heavy synoptic snow will
draw to an end, but impressive NW winds and CAA in its wake will
bring a period of widespread lake effect snow (LES) to the Great
Lakes. Although the lake temperatures are cold, below +5C, and
there is considerable ice cover according to GLERL, 850mb temps
crashing to around -20C will create steep lapse rates and
impressive inversion heights with pronounced omega into the near-
surface DGZ. This should be more than sufficient to support heavy
LES, with rates above 1"/hr (30-60% chance). While the duration of
heavy LES may be somewhat limited as winds begin to weaken and veer
as the low pulls away, there is sufficient time for locally heavy
accumulations in the favored NW snow belts. WPC probabilities for
LES are high D1 (>70%) for 4+ inches in the NW L.P. of MI near
Traverse City, the far SW portions of the L.P. of MI, and greater
than 50% along the Chautauqua Ridge and the Tug Hill Plateau. LES
wanes in coverage D2 but persists heavily east of Lake Ontario
where probabilities remain elevated (50-90%) for an additional 4+
inches through Tuesday night.

...Central Appalachians & Mid-Atlantic states... Days 1-2...

The strong low pressure /blizzard/ over the Great Lakes will
steadily move northeast into Canada today, while the parent upper
trough amplifies into the Tennessee Valley and takes on a negative
tilt. This will push a powerful arctic cold front eastward across
the Ohio Valley, Central Appalachians, and Mid-Atlantic states
today. As this front races east, temperatures will plummet on
strong CAA, while mid and upper level flow remains southerly in
response to the strongly tilted and digging upper trough. This will
likely result in precipitation changing over to snow before ending
in most areas.

While most of this snow will just be conversational, in the colder
climates of the higher elevations of the Central Appalachians, this
may result in a two-pronged event consisting of heavy snow. The
first will be directly behind the front as p-type changes rapidly
from rain to snow, leading to a brief period of snowfall rates
exceeding 1"/hr (40-60% chance) from the Central Appalachians
through the Laurel Highlands and into the Finger Lakes region of
NY. During this time, however, snowfall accumulations will be
modest at just a few inches at most. However, in the wake of this
front, the increasing CAA on NW flow will drive potent upslope
ascent into the Central Appalachians Monday night through Tuesday
aftn. Although the column is dry aloft, the DGZ will lower to near
the surface, leading to favorable ascent due to the upslope to
maximize snow growth. This should cause accumulating snowfall in
the higher elevations of WV, where WPC probabilities peak above 50%
for 6+ inches of snowfall.

Finally, as the trailing vorticity maxima and secondary shortwave
embedded within the trough finally kicks east Tuesday aftn/eve,
convective snow showers and isolated snow squalls could develop
across this area. Additional snowfall accumulations will be light
with any of these convective elements, but briefly heavy snow rates
and gusty winds could cause local travel impacts.

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

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