077
FXUS63 KMQT 041140
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
640 AM EST Thu Dec 4 2025

.KEY MESSAGES...

- Winter Weather Advisory remains in effect until the early
afternoon for an additional 2-4 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 this morning and southwest gusts up
to 40 knots tonight. 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 below zero across much of the U.P. tonight.

&&

.DISCUSSION...
Issued at 447 AM EST Thu Dec 4 2025

Early morning KMQT radar returns show light lake effect snow showers
for Marquette County and west with several stronger NW-wind LES
bands over Alger, Schoolcraft, and Luce Counties. Observations show
that the temperatures across much of the interior UP have fallen to
the single digits, with the current lowest temperature being
reported in the Watson region of southern Marquette County at
negative 3. 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 flow around 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 little change in the structure and location of
LES bands until around 18Z today. As 850mb temps remain in the
negative 20s C over a Lake Superior still around 5 C, thermodynamic
support for the bands will remain healthy. Throughout today, as a
surface high skirts to the south of the Great Lakes, ridging
will bring dry air, falling inversion heights, and eventually
will back the winds to be offshore this afternoon. Thus, while
the Winter Weather Advisory has been extended to 18Z in the east
(2-4 additional inches of accumulation expected), LES will
definitely cease for at least some period this afternoon and
evening in the east. As the winds shift out of the west to
southwest, some LES will linger over the Keweenaw Peninsula, but
accumulations should be 1" or less. Besides the precipitation,
gusty NW winds will continue this morning in the east especially
along Lake Superior as cold advection behind the low helping
wind gusts of 35+ mph mix down to the surface. 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 for the morning commute. While
the winds will relax some as ridging moves over the UP this
evening, not much temperature relief is expected with the
typically warm southwest winds, as highs today are only forecast
to be in the teens, and perhaps cooler in the interior west.

The next pair of floats in this parade of clipper lows/fronts comes
tonight and Friday evening, both with surface lows around 1004 mb.
Neither feature looks particularly impactful in terms of synoptic
precipitation, though the lake effect snow portion may be more
impactful. NAM soundings for Munising show a warm nose (note: not
above freezing, so no precip type issues) that keeps much of the
saturated profile warmer than the DGZ, so snow ratios might not be
as high as what`s been observed with the ongoing LES. Additionally,
moisture itself might be a challenge as even the moist-biased NAM
struggles to saturate much of the near-lake surface layers, likely
due to the aforementioned ridging drying things out as well as the
nature of NW flow being more continental (and thus, dry) compared to
a more summery pattern or a CO Low pattern where there is a Gulf
connection to provide moisture transport. All this to say, snow
accumulations may be an inch here, a couple inches there, but
chances of 4+ inches of snow in any given day are 20% or less within
this pattern.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 640 AM EST Thu Dec 4 2025

Mainly MVFR conditions are expected at IWD and CMX through the TAF
period except for a short duration of VFR this evening with gusty
southerly winds helping to push lake effect clouds and snow showers
away from the TAF sites. SAW will likely see a longer period of VFR
from mid-morning through the evening. A strong low level jet will
bring LLWS to IWD this evening. Tonight MVFR conditions come back as
low clouds increase in coverage along with a chance for light snow,
covered with PROB30s.

&&

.MARINE...
Issued at 447 AM EST Thu Dec 4 2025

Northwest gales fall below 35 kt in the east this morning, however,
southwest winds ahead of the next Clipper Low will ramp up in the
west this evening to gales of 35 kt, spreading across the rest of
the lake up to 40 kt tonight. While heavy freezing spray is an
ongoing threat with the first gale this morning, freezing spray
rates will be more moderate with the gale this evening into Friday.
Waves in the east will quickly fall from 12-15 ft to below 8 ft by
this afternoon. In the west, waves quickly ramp up to 9-13 ft
tonight. Friday, wind gusts fall to near 20 kt and waves fall to
near 4 ft. Saturday morning, post-frontal northwest winds will ramp
up to 30 kt, with chances of a brief 35 kt gale around 40 percent.
The weather pattern into next week looks to continue with periodic
Clipper Lows that will bring either increased southwest winds ahead
of it and/or gusty northwest winds in its wake.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Weather Advisory until 1 PM EST this afternoon for
     MIZ006-007-085.

Lake Superior...
  Gale Warning from 4 PM EST /3 PM CST/ this afternoon to 4 AM
     EST /3 AM CST/ Friday for LSZ162-240>242-263.

  Gale Warning until 7 AM EST this morning for LSZ243>248-264-
     265.

  Gale Warning from 7 PM this evening to 7 AM EST Friday for
     LSZ243>251-264>267.

  Heavy Freezing Spray Warning until 7 AM EST this morning for
     LSZ244-263-264-266.

  Gale Warning until 10 AM EST this morning for LSZ249>251-266-
     267.

Lake Michigan...
  Gale Warning from 10 PM this evening to 7 AM EST Friday for
     LMZ221-248-250.

&&

$$

DISCUSSION...GS
AVIATION...NL
MARINE...GS