068
FXUS63 KMQT 242325
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
625 PM EST Mon Nov 24 2025

.KEY MESSAGES...

- Winter Storm Watches are in effect for much of the UP as a
deepening low pressure tracks across the UP Tuesday and Wednesday
with an eventual transition to lake effect snowfall. Chances of 12
inches or more of snow are over 90 percent across the western UP by
Thanksgiving.

- Wind gusts of 25-35 mph are expected Wednesday, with some gusts to
45 mph or more possible over the Keweenaw. The combination of wind
and moderate to heavy snowfall could make Thanksgiving holiday
travel very difficult to near impossible at times.

- Gales up to 45 kt are expected (70-90%) on Lake Superior Tuesday
night through Thursday, with near 50% chances for Storm-force gusts.
Wave heights of 12-18 ft are expected, with some spots near Stannard
Rock and between Marquette and Grand Marais seeing up to 18-20 ft
waves.

&&

.DISCUSSION...
Issued at 409 PM EST Mon Nov 24 2025

GOES-East Day Cloud Phase imagery shows some high to mid level
clouds over the southern tier of the UP, with a few fair-weather cu
over the far eastern UP. The high clouds are streaming in ahead of a
500mb trough over the Central and Southern Plains, though with that
trough weakening and being more positively tilted as time goes on,
precipitation associated with that trough beginning tonight will be
low-impact. HREF mean accumulated precipitation by noon tomorrow is
only around a quarter of an inch over the south-central, down to a
tenth of an inch or less for the north half. With the cloud cover
and precipitation, low temperatures tonight are less than 10 percent
likely to fall below freezing.

Attention then turns to an upstream digging trough that is currently
over Montana and is expected to deepen and become negatively tilted
as it progresses through the Upper Midwest Tuesday through
Wednesday. This is a prime setup for strong dynamic forcing for
precipitation, and the ensembles are converging on a surface
solution that brings a mid 990s mb low pressure over the central UP
by 12Z Wednesday and to the lower 990s to upper 980s mb over the
eastern UP by 18Z Wednesday. Dynamic cooling within the profile is
allowing for the CAMs to show precip types becoming 40-50% likely to
be snowfall in the west as soon as early afternoon Tuesday, though
accumulation will be difficult as rain mixing in as well as warm air
and ground temperatures inhibiting accumulation early. However, by
Wednesday as cool air wraps in behind the low pressure, the western
UP will see snow ratios climbing from below 10:1 early in the
morning to over 15:1 by the afternoon. This cold advection will also
help mix 30-40 mph wind gusts from aloft down to the surface in the
wake of the low. HREF joint probabilities of wind gusts over 35 mph
and snow rates sufficient to drop visibility below a quarter of a
mile are 40-70% from Copper Harbor to Ironwood, indicating growing
potential for blizzard conditions. 850mb temperatures falling into
the negative teens C over Lake Superior water temperatures around 5
C will allow for lake enhancement of the synoptic precipitation
eventually becoming lake effect, and the western UP will also get a
orographic boost as winds will be perpendicular to the terrain
of the Copper Country. As lake effect ramps up behind the low
later Wednesday into Thursday and rain turns to snow across the
east, snow totals will begin to ramp up over the eastern UP as
well, with snow totals increasing in the LREF to over 8 inches
along the Lake Superior shores from Marquette to at least Alger
County if not into Luce County. Winter Storm Watches have been
expanded into Iron and Marquette County for the synoptic
precipitation and watches have also been hoisted for the eastern
UP for primarily post-system lake effect snowfall. At this
point, sources of uncertainty are primarily in the snow ratios,
mesoscale enhancements or dry slots, and how well the gusty
winds aloft can mix to the surface. However, with the chances of
1"/hr snowfall rates in the west increasing to 70+ percent on
Wednesday sustained over a long period of the day, confidence is
high that the pre-Thanksgiving travel period will become
hazardous over the western UP.

Given the supportive thermodynamics, lake effect snowfall is
expected to linger at least over the eastern UP through Thanksgiving
and towards the weekend, though with the complexity of the
shortwaves interacting prior to Thanksgiving, spread is high on how
well ridging will be able to move in and bring cessation of showers
as well as whether any further clipper shortwaves will be able to
impact the UP.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 624 PM EST Mon Nov 24 2025

VFR conditions are expected through the evening. Later this evening
MVFR CIGs will begin to push north into the area ahead of a strong
winter storm system. Expect IFR conditions to develop as showers,
fog and low clouds overspread the area Tuesday morning. By late in
the TAF period (Tuesday late afternoon) LIFR conditions will
develop as rain intensity increases and snow begins to mix in
over at CMX and IWD.

&&

.MARINE...
Issued at 409 PM EST Mon Nov 24 2025

As high pressure passes southeast of the Great Lakes, wind gusts
will remain below 20 kt tonight. Attention then turns to a merger of
upper-level systems resulting in a deepening surface low pressure
passing over the Michigan UP late Tuesday and over eastern Lake
Superior Wednesday. Ahead of the low, northeasterly wind gusts
increase to 25-30 kt Tuesday night, then to high-end gales to 45-48
kt by Wednesday morning. Chances of storm-force gusts to 50 kt have
increased to near 50 percent by Wednesday evening. Should
probabilities of storm-force winds remain elevated and are supported
by hi-res model guidance tonight, Storm Warnings may be necessary,
though Gale Watches will remain for this package. Winds will remain
at least 50 percent likely to exceed gale force until overnight
Thursday into Friday before falling to 20-25 kt Friday and below 20
kt overnight into Saturday. During the high-end gale, wave heights
will increase to 8-16 ft lakewide, with the areas from Stannard Rock
to Munising Bay seeing potential for 18-20 ft waves.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Storm Watch from Tuesday evening through Thursday
     morning for MIZ001>004-009-084.

  Winter Storm Watch from late Tuesday night through Thursday
     morning for MIZ005-010.

  Winter Storm Watch from Wednesday afternoon through Thursday
     evening for MIZ006-007-013-014-085.

Lake Superior...
  Gale Watch from Tuesday evening through Thursday morning for
     LSZ162-240>242-263.

  Gale Watch from Tuesday evening through Thursday evening for
     LSZ243-244-264.

  Gale Watch from late Tuesday night through Thursday evening
     for LSZ245>248-265.

  Gale Watch from Wednesday morning through late Thursday night
     for LSZ249-250.

  Gale Watch from Wednesday afternoon through late Thursday
     night for LSZ251-267.

  Gale Watch from late Tuesday night through late Thursday night
     for LSZ266.

Lake Michigan...
  Gale Watch from Wednesday afternoon through Thursday afternoon
     for LMZ221-248-250.

&&

$$

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