794
FXUS63 KMQT 071946
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
246 PM EST Sun Dec 7 2025

.KEY MESSAGES...

- A pair of clipper systems are set to bring accumulating snow
  Monday night through Wednesday. Stay tuned for additional
  details regarding snowfall amounts and any potential Winter
  Weather Headlines.

- Southwesterly gales up to 35 knots are possible (50-90%
  chance) over eastern Lake Superior Monday evening. Northeast
  to northerly gales are possible (50% chance) once again over
  the lake late Tuesday night through Wednesday morning, in
  addition to moderate freezing spray.

- Cooler than normal temperatures continue through this week and
  beyond. Low temperatures in the single digits to near zero are
  expected tonight and are possible late this week into this
  upcoming weekend.

&&

.DISCUSSION...
Issued at 245 PM EST Sun Dec 7 2025

As ridging builds into the region today, the cold air aloft is
allowing light lake effect snow showers to continue over the
northwest wind snow belts this afternoon, with an additional fluffy
inch or two still possible over the east give the longer fetch over
Lake Superior (less than an inch is expected over the western
northwest wind snow belts this afternoon into this evening). As the
zenith of the ridging passes through the U.P. tonight, expect to see
the lake effect mostly end over the northwest wind snow belts as any
remaining showers are `pushed` out into the lake. The area that may
be exempt is near the lakeshore from Grand Marais east towards
Whitefish Point, where the winds don`t look to turn southwesterly
until after sunrise on Monday. Otherwise, while there may be a stray
shower or two over some spots like the Keweenaw late tonight, expect
the impacts to be near nothing. The ridging will allow skies to
clear out across much of the area though; this will cause
temperatures tonight to drop down to at least around zero in many of
the interior areas. Given the expectation for radiational cooling
during the overnight hours, went towards the lower end of guidance
and did a blend of the NBM and NBM10th percentile; this brings low
temperatures down into the negative single digits across most of the
interior areas, with the coldest spots (such as north Iron County)
potentially even going colder than forecasted (think closer to
around -10F). Therefore, if you have any outdoor animals, double
check and make sure that they will be warm throughout the overnight
hours as the frigid temperatures will not be all that fun to be in;
the one saving grace is that the winds will be pretty calm, which
will help the wind chill stay closer to zero than the negatives.

The main `action` so-to-speak comes with the arrival of two Clipper
lows across the Upper Midwest. The first looks to arrive Monday
night over Lake Superior, whereas the second looks to move through
Wisconsin into Lower Michigan Tuesday night through Wednesday
morning. For the first and weaker Clipper, guidance has it moving
through the Northern Plains before arriving over Lake Superior late
Monday night. As this happens, we could see some rare southwest wind
lake effect snowfall kick-off from Lake Michigan and impact the
eastern U.P. east of Manistique as soon as late Monday afternoon.
While delta-Ts will lower as the first Clipper approaches, with
inversion heights up to around 10 kft, increasing moisture flux with
time due to increasing winds over Lake Michigan`s sfc, and slight
convergent flow over the lake, we could see light to occasionally
moderate (1/2 inch or greater per hour; up to around a 30% chance)
snowfall rates before the synoptic scale forcing brings enhancement
late in the night/early Tuesday morning. As the Clipper arrives, a
band of moderate to potentially even heavy (1+ inch per hour
snowfall rates) snowfall looks to make its way across the U.P. from
west to east during the overnight hours; as of the 06z RRFS run, the
chance for 1 inch per hour or greater snowfall rates ranges from 30
to 60% across the U.P. Monday night. While this may cause anywhere
from 2 to 4 inches to fall across most of Upper Michigan, over where
the now lake-enhanced band is set up over the eastern U.P., snow
totals could be 6 inches or more as heavy snowfall rate chances are
highest (and linger the longest) over there. While the moderate to
heavy snowfall looks to move through too fast to hoist up Winter
Weather headlines across much of Upper Michigan Monday night to
Tuesday morning, a Winter Weather Advisory may be needed over the
eastern counties, particularly Luce County where the highest totals
are expected (save for western Mackinac County). As this Clipper
gets absorbed by the stronger Clipper digging through the Northern
Plains towards the Upper Midwest on Tuesday, expect light lake
effect snow to develop over the west wind snow belts Tuesday.

Model uncertainty has decreased since yesterday on the track of the
second, stronger Clipper low. Most models are now bringing the track
of the low a little further south as of the 12z runs, save for the
NAM which is the more northerly outlier. Therefore, thinking
snowfall amounts will be closer to only a couple to few inches, with
the most synoptic-scale snowfall being realized over Menominee
County. However, should the CAMs come in and pick up greater
moisture flux from the Great Lakes and increased forcing from
upslope flow, we could see enhanced snow totals over the central and
eastern U.P. Tuesday night into Wednesday in comparison to the
current forecast. Again, will continue to monitor this system as the
forecast evolves with time. As of right now, though, looking like we
may just see some fluffy snow bringing some minor traffic impacts to
the area (low visibilities and quickly accumulating snow at times,
drifting, etc.).

Moving into the latter half of the week and into this upcoming
weekend, lake effect snow looks to continue over mainly the
northwest wind snow belts as a couple of weak shortwaves (and a
slightly stronger Clipper late in the week) keep the lake effect
snow machine going. With a shot of very cold Arctic air moving down
into the eastern 2/3rds of the CONUS late this week into this
upcoming weekend, expect the below normal temperatures to continue,
with some below zero low temperatures possible late this week
through this weekend. Thanks to the recent stratospheric warming
event and the rex block over the Pacific, thinking the colder than
normal air will generally continue through the end of the forecast
period and potentially even beyond.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1209 PM EST Sun Dec 7 2025

Lake effect snow showers will continue downwind of Lake Superior
this afternoon from the northwest. These will primarily impact
KIWD/KCMX before easing this evening. Until they do, IFR is expected
at these sites and MVFR at KSAW. As winds shift to southwesterlies,
another round of snow may move into KCMX tonight, but confidence
isn`t very high, so prob30 groups were introduced. Otherwise, all
sites should trend to VFR this evening and light winds take hold.

&&

.MARINE...
Issued at 245 PM EST Sun Dec 7 2025

Northwesterly winds of 20 to 30 knots over the eastern half of the
lake dwindle to 20 knots or less tonight as the zenith of sfc high
pressure ridging moves through the region. With the weakening of the
winds, we will also see a cessation of moderate freezing spray over
the eastern half of the lake as well by this evening. That being
said, winds look to increase from the southwest on Monday ahead of a
Clipper low moving from North Dakota into Lake Superior Monday
afternoon to Monday night; gusts of 25 to 30 knots are expected to
make a return lake-wide by Monday evening, in addition to some
moderate freezing spray near Isle Royale as well; there is even a 50
to 90% chance for gale-force gusts up to 35 knots Monday evening
over the eastern lake, with the highest chances just off of the
southeastern shoreline (from Marquette eastwards). As the low stalls
out over the lake Monday night and starts to get absorbed by a
stronger Clipper low moving through the Northern Plains on Tuesday,
expect the winds to weaken as they veer west and eventually
northwest with time, eventually becoming 20 knots or less again by
early Tuesday evening.

The light winds do not stay around for very long though, as the
second, stronger Clipper low moves through Wisconsin and Lower
Michigan Tuesday night and Wednesday, respectively. As this occurs,
winds veer to the northeast and increase up to around 30 knots, with
a 50% chance for gales up to 35 knots possible Tuesday night into
Wednesday morning; winds back to the north with time late Tuesday
night through Wednesday as the Clipper passes by to the south, with
moderate freezing spray returning through the end of the day
Wednesday as well. While winds look to lighten Wednesday evening,
additional shortwaves moving through the region late this week
through this upcoming weekend are projected to bring gustier
northwesterly winds (and freezing spray) back across Lake Superior
from time-to-time for the rest of the forecast period; the strongest
shortwave looks to be a Clipper low moving through late this week
which could bring northwesterly gales up to 35 knots and moderate
freezing spray back across the lake late Friday into Saturday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

DISCUSSION...TAP
AVIATION...JTP
MARINE...TAP