102
FXUS63 KMQT 241122
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
622 AM EST Mon Nov 24 2025

.KEY MESSAGES...

- Confidence continues to increase on an impactful winter
  weather event late Tuesday into Thanksgiving. 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
  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 a 30-40% chance for
  Storm-force gusts. Wave heights of 12-18 ft are expected, with
  some spots near the tip of the Keweenaw and between Marquette
  and Grand Marais seeing up to 16-19 ft waves.

&&

.DISCUSSION...
Issued at 324 AM EST Mon Nov 24 2025

Some mid-level clouds are hanging out over the Upper Peninsula early
this morning as sfc ridging gives way to a lower-level troughing
pattern today. However, with model soundings showing a robust dry
layer below 8 kft, no precipitation is expected to hit the ground
today; if anything does, expect only light drizzle at the utter
most. If you`ve got any last minute fall projects that need to be
done, today is the day to do it as the weather looks to be pleasant,
with highs once again creeping up into the 40s to potentially even
lower 50s as south to southwesterly winds blow throughout the day.

The quiet part of the forecast period ends this evening as two
shortwave lows, one moving through the Northern Plains and another
lifting through the Southern Plains, phase with one another over the
Upper Mississippi Valley on Tuesday. As this occurs, light rain
begins to creep into the southern half of the U.P. tonight, with
rainfall picking up slightly and overspreading the rest of Upper
Michigan Tuesday. Overall, not much rainfall is expected tonight
through Tuesday as the shortwaves are not expected to be
synoptically deep; thus, synoptic-scale forcing associated with the
warm frontal ascent will be somewhat limited and keep things on the
lighter side. That being said, the NBM ensemble suggests that
anywhere in the U.P. has a 40 to 70% chance of seeing at least a
quarter inch of precipitation between tonight and Tuesday evening,
which would produce at least a wetting rainfall across portions of
the Upper Peninsula.

The `headliner` so-to-speak for this forecast period is the
snowfall, which is expected to start accumulating over the western
U.P. Tuesday evening as temperatures finally cool to and below
freezing. However, as the phasing of the lows occur Tuesday over the
Upper Mississippi Valley, improving synoptic-scale forcing over the
western U.P. could induce dynamic cooling within the profile,
causing the rain to switch over to snowfall earlier in the day;
snowfall could start accumulating as early as early Tuesday
afternoon (see the 00z NAM3km and GFS for examples). However,
confidence on this happening is still rather low at this time, as
this will still be during the daylight hours and could be affected
by the timing and track of the phasing shortwave lows. However,
confidence on the transition over to snowfall over the western U.P.
increases Tuesday evening as the now-almost-completely phased low
starts to deepen. With warm air advection continuing to pump Gulf
moisture into the low pressure system Tuesday night and Wednesday
over the central and eastern U.P., current guidance has a potential
TROWAL developing over the Keweenaw and western U.P. Tuesday night
into Wednesday as cold air north and behind the low moves over the
western third of our CWA, with the cold air advection progressing
eastwards with time Tuesday night through Wednesday as the low lifts
towards Canada. As the TROWAL looks to generally remain settled over
the Keweenaw and west Tuesday night into Wednesday, expect several
hours of moderate to heavy accumulating snowfall. In addition,
expect the winds to increase with time Tuesday night through
Wednesday across all of Upper MI, creating a blowing snow threat
too, especially as the snowfall transitions to lake enhanced and
eventually pure lake effect Wednesday into Wednesday night. The high
snowfall rates and lower visibilities due to the blowing snow
potential could make travel very difficult to downright dangerous at
times, especially over the western U.P. and the Keweenaw where the
greatest snowfall amounts are expected; up to 12 inches of snowfall
is almost guaranteed across the western U.P. between Tuesday night
and Thursday morning according to the NBM (90+% chance). Therefore,
a Winter Storm Watch has been hoisted up for Gogebic, Ontonagon,
Houghton, Baraga, and Keweenaw counties to account for the
potentially significant snowfall and dangerous travel conditions.

As the low begins to lift away towards northern Quebec later
Wednesday, expect the transition over to lake enhanced snowfall
across the rest of the U.P. from west to east as the TROWAL slowly
starts to slide eastward with the low. While some snowfall could be
seen in the south central areas, expect accumulations to limited to
a couple of inches as the more impactful snowfall falls closer to
(and just uphill from) Lake Superior. With the lake waters being at
around 5 to 6 C before this event, the stronger winds off of the
lake may bring the warmer air over the waters to the immediate
nearshore, limiting snowfall amounts in areas like Ontonagon, Copper
Harbor, Baraga/L`Anse, Marquette/Harvey, and Munising proper (not up
in the hills). However, with the strongest winds expected near the
lakeshore, expect the greatest blowing snow impacts to be seen in
and around these areas (like M-28 from Marquette to Munising) once
the snow starts to stick. Given the strong winds, even as we
transition to pure lake effect snow from the northwest wind snow
belts late Wednesday into Wednesday night/Thursday, expect the snow
ratios to not be too much higher than 10:1; thinking they will range
from the lower to mid teens as snowflakes have a higher chance of
fracturing in the high winds. Nevertheless, some spots may see
higher snow ratios of 20+:1 at times as the inversion heights within
some of the lake effect bands could get up to 10 kft or greater(!),
with forcing maximized in the DGZ. While the chance is not high,
thinking the NBM is correct to produce a 10% chance for thundersnow
over the eastern lake Wednesday night given that some small amounts
of MUCAPE are being seen within the model guidance. Thus, while they
look to miss out on the TROWAL over the western U.P. Tuesday night,
the northwest wind snow belts as well as northern Marquette County
could see moderate to heavy lake enhanced to lake effect snowfall at
times Wednesday into Thursday; don`t be surprised if additional
Winter Weather Headlines are issued for these areas in the future.

Northwest lake effect snowfall continues across the region through
the Thanksgiving holiday into Friday and potentially even Saturday
too. While the lake effect snowfall and blowing snow is expected to
not be as bad on Thanksgiving as it will be Tuesday night through
Wednesday, we could still see some moderate to occasionally heavy
lake effect snow bands over the northwest wind snow belts from time
to time on Thursday, with blowing snow occasionally reducing
visibilities further along and near the Lake Superior shoreline. As
the troughing and cold core aloft weaken over us late this week,
expect the lake effect snowfall over the northwest wind snow belts
to lighten up, potentially even ending over the west half by late
Friday. Given the larger fetch, however, it looks like lake effect
snow will continue over the east at the very least until this
weekend.

The colder than normal temperatures look to continue across the area
into early next week as polar air plunges towards the Desert
Southwest. While predictability is low at this time, we may see a
shortwave or two bring accumulating snowfall back across the area
sometime late this weekend and/or early next week as Gulf air tries
to push northwards against the polar air.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 621 AM EST Mon Nov 24 2025

VFR conditions are expected through most of the TAF period. Mid to
upper level clouds currently over the area begin to move out over
the next couple of hours, but more cloud cover moves in by the
afternoon. Ceilings begin to lower late in the TAF period (after
02Z) as a storm system approaches the area, with MVFR and eventually
IFR first developing at KSAW after 02Z and then at IWD and CMX after
06Z.

&&

.MARINE...
Issued at 340 AM EST Mon Nov 24 2025

As weak troughing moves over the Upper Great Lakes today, expect the
south to southwest winds of 20 to 25 knots over the western and
eastern lake to continue until late this afternoon, with gusts up to
30 knots possible over the far eastern lake late this morning. While
we can expect a short reprieve in the winds this evening, expect the
winds to begin picking back up over the western half of the lake
starting Tuesday as two shortwave lows, one moving over the Northern
Plains and the other lifting from the Southern Plains, phase with
one another over the Upper Mississippi Valley. This will cause winds
to increase from the northeast throughout the day, eventually
bringing northeast gales up to 35 knots to the western lake by
Tuesday evening. As the nearly-phased low continues towards Lake
Superior Tuesday night, expect the winds to slowly become more
northerly with time as the gales increase to 45 knots; a few storm-
force gusts up to 48 knots, while not expected could be seen from
time to time (30 to 40% chance according to the NBM). In addition,
waves will begin to swell to 12 to 16 ft across the western half of
the lake. As the low moves through Lake Superior on Wednesday and
continues to deepen as it heads towards northern Quebec, expect the
winds to slowly continue backing to the northwest with time, with
wave heights increasing to 14 to 19 feet over the north central and
eastern lake behind the low. As cold air advection continues to
cycle in from the northwest Wednesday night through Thanksgiving, we
could see some light freezing spray develop across the lake as gales
of 35 to 45 knots slowly weaken with time from west to east,
eventually ending late Thursday night. As weak high pressure ridging
moves overhead late this week into this weekend, expect the winds to
die down to 20 knots or less again.

&&

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

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...TAP
AVIATION...LC
MARINE...TAP