395
FXUS63 KMQT 031744
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1244 PM EST Wed Dec 3 2025

.KEY MESSAGES...

- A Winter Weather Advisory is in effect for 3-7 inches of snowfall
in the eastern UP associated with NW wind lake effect snow bands.

- Gale Warnings are in effect for much of Lake Superior for
northwest winds up to 40 knots today and tonight. Additional gale
potential (30-50% chance) exists Thursday evening into Friday. Both
rounds will be accompanied by moderate to heavy freezing spray and
waves of 8+ ft.

- Colder than normal temperatures continue through the forecast.
Expect wind chills in the single digits above and below zero
Wednesday into Thursday.

&&

.DISCUSSION...
Issued at 454 AM EST Wed Dec 3 2025

Early morning KMQT radar returns show widespread light to moderate
snow showers across Upper Michigan, with some breaks in the western
UP in particular. Observations show that the winds have as of 09Z
shifted to be out of the northwest behind the front in the western
third while southwesterly winds prevail ahead of the front in the
east and central. Aloft, few longwave features are noted at 500mb
over North America, with the dominant feature being a Hudson Bay
closed low with a few shortwaves embedded within the peripheral
flow. Elsewhere, a Rex Block is set up off the Pacific Coast, with
the closed low being off the coast of Los Angeles and the Baja
California, while the ridging is off the Pacific Northwest and
British Columbia coast. As this blocking pattern is in no hurry to
progress (especially as the number of longwave features downstream
is low), the weather pattern over Upper Michigan will be dictated by
the aforementioned embedded shortwaves within the Hudson Low and any
shortwaves embedded in the northwesterly flow proceeding through the
Canadian Rockies. Either shortwave mechanism is primed to deliver
clipper-type low pressure systems, though given the diminutive size
of the parent troughing features, these clippers will not be
particularly strong. However, the cyclonic surface flow and shot of
cool air over the warm Great Lakes that come with each clipper will
mean that the more impactful weather this forecast period will be
the post-system LES.

For today, CAMs show snowfall quickly becoming banded in nature,
aligning with the typical NW wind LES bands. 850mb temps falling
into the -20s C over a Lake Superior still around 5 C will mean that
the thermodynamic support for the bands will be healthy. Soundings
for the Munising area show inversion heights growing to around 7.5
kft, though given just how cold the lower levels are, the DGZ is
somewhat shallow at around 2 kft and the bottom of the DGZ is not
fully saturated. The HREF gives chances of snowfall rates exceeding
0.5"/hr at only around 30% in the east today. Given the mixture of
supportive and not-so-supportive forecast elements, have elected to
go with a Winter Weather Advisory for the east, with snowfall totals
expected to be in the 3-7 inch range for the NW wind LES belts. An
isolated report of 8+" cannot be ruled out (30%), but reports that
high will be the exception, and not the rule. Besides the
precipitation, wind will also complicate matters, with the cold
advection behind the low helping wind gusts of 35+ mph mix down to
the surface, especially near the lakeshores. In conjunction with the
falling snow, the wind will cause some lower visibility at times and
snowdrifts over some roads, which could make travel difficult in
some spots at some times. By Thursday afternoon, local surface
ridging will help shift winds to be out of the SW to SSW, fully
shifting LES bands offshore, though not before the coolest high
temperatures of the season are forecast, with NBM highs on Thursday
only in the low teens in the interior west.

While high temperatures in the teens and 20s persist throughout this
week and into the weekend, not much change in Lake Superior`s
temperature is expected until some clearing skies can allow for more
efficient cooling. With persistent cool NW flow aloft over the warm
lake for the foreseeable future, expect some flavor of LES to
persist between rounds of clippers, the following of which, the NBM
brings increased PoPs with late Thursday night into Friday morning.
Again, given the weaker nature of these systems, the lake effect may
be the more noteworthy mechanism for delivering accumulating
snowfall, and with persistent background NW flow, expect the NW wind
snow belts to be the hardest hit this week and into the weekend.
Overnight lows in the single digits to occasionally subzero in the
interior west will bring some of the coolest temperatures of the
season, with Thursday morning being the most likely to have wind
chills below -15 (50-80% chance from Iron River to Ironwood, 30%
rest of the interior).

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1244 PM EST Wed Dec 3 2025

Lake effect snow showers and associated visibility reductions will
continue to be the main forecast hazard on the 18Z TAF cycle.
Currently there is somewhat of a lull in the activity which should
continue through the mid-afternoon/evening. However, a reinforcing
shot of cold air will reinvigorate the snow showers this evening
into the overnight hours at IWD/CMX, with CMX standing the best
chance for IFR conditions (>50%) with a combination of snow and
blowing snow. Northwest winds will continue gusting to 20-25 kt
through the overnight, up to 30 kt at CMX. Variable visibilities can
be expected through the overnight period with vsby bouncing mainly
between MVFR/IFR for CMX and IWD and VFR/MVFR for SAW which looks to
be on the outer fringes of the more persistent LES bands. Ceilings
look to remain mostly MVFR except with some VFR at SAW. Winds back
from northwesterly to southwesterly late tonight into Thursday
morning which will push LES bands out of the terminal corridor and
result in ceilings scattering.

&&

.MARINE...
Issued at 454 AM EST Wed Dec 3 2025

Gale Watches have been upgraded to Warnings for today as the post-
cold front winds will gust to 35-40 kt out of the northwest today
and tonight, driving waves of 8-12 ft across the lake (locally up to
15 ft north of Grand Marais, MI). As a weak ridge moves over the
lake Thursday, wind gusts fall to near 25 kt, backing to the west,
then southwest. Ahead of the next clipper low, gales to 35 kt are
once again expected across Lake Superior associated with the pre-
front southwesterlies. Winds slowly decrease Friday to near 20 kt
out of the west. Into the weekend and beyond, expect the pattern of
periodic weak clipper low pressure systems to continue with cooler
than normal temperatures. Because of the occasionally frigid
temperatures, moderate heavy freezing spray can be expected with the
periods of strongest wind, with heavy freezing spray forecast
tonight, even as some of the Gale Warnings end.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Weather Advisory until 7 AM EST Thursday for MIZ006-007-
     085.

Lake Superior...
  Gale Warning from 4 PM EST /3 PM CST/ this afternoon to 1 AM
     EST /midnight CST/ Thursday for LSZ241-242-263.

  Gale Warning until 7 AM EST Thursday for LSZ243>251-264>267.

  Heavy Freezing Spray Warning from 7 PM this evening to 7 AM
     EST Thursday for LSZ244-263-264-266.

Lake Michigan...
  Gale Watch from Thursday evening through Friday morning for
     LMZ221-248-250.

&&

$$

DISCUSSION...GS
AVIATION...Thompson
MARINE...GS