602
FXUS63 KMQT 071122
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
622 AM EST Fri Nov 7 2025

.KEY MESSAGES...

- Lake effect rain showers will develop today and transition to
  snow showers as temperatures fall in the afternoon and
  evening. Minor accumulations (mainly an inch or less) are
  expected in the north- northwest wind snowbelts.

- While not unusual for November, the coldest airmass so far
  this season will arrive this weekend bringing accumulating
  lake effect snow showers along with highs in the 30s and lows
  in the teens/twenties. The probability for impactful snowfall
  is increasing, with a 30-60% chance for 6"+ late Saturday
  night through Sunday night.

&&

.DISCUSSION...
Issued at 403 AM EST Fri Nov 7 2025

KMQT radar returns as of 08Z show a widespread precip shield over at
least the eastern two-thirds of the UP. This precip is ahead of a
RAP-analyzed 996mb low over the Ironwood area and with a shortwave
embedded within large-scale troughing over much of eastern Canada
and the Great Lakes basin. Reinforcing shortwaves further back in
the Plains will support secondary cold fronts that will usher in the
coolest airmass of the season by this weekend, though the NAEFS
suggests that the temperatures will only be around the 10th
percentile of climatology (low, but not unusually so). When compared
to Lake Superior`s water temperature still running warmer than
normal by as many as 4 degrees (currently just under 50 F when
normal is just under 46 F), even a slightly cool airmass will give
prime conditions for lake-enhanced to lake-effect precipitation,
which will characterize much of this forecast period.

Models show that synoptic precipitation will largely depart the UP
by around 12Z this morning, though hi-res guidance already begins
ramping up post-frontal lake effect showers over the western UP by
this time. As winds ramp up out of the north to northwest this
afternoon (with the rapid pressure falls/rises helping bring some
gale-force gusts to the Lake Superior shores), temperatures fall
enough this afternoon to bring a transition from rain to snow
showers in the north to northwest wind lake effect bands. This will
be pretty brief however, as the rising surface pressure and
approaching surface ridging will dry out the low levels and bring an
end to most showers tonight, save for a few models which hold on to
light snow showers over the Alger Co/Marquette Co line tonight.
Overall, generally less than a half inch of snowfall is expected,
except for some rural locations along the high terrain along the
Baraga Co/Marquette Co line where up to an inch of snow is forecast
(60-80% chance in the HREF).

A pair of prominent shortwaves will then pivot towards and through
the Great Lakes basin this weekend, still embedded within the large
scale troughing over northeastern North America. The first will
pivot around the southern periphery of the Great Lakes, and while
the synoptic precip will remain well to the south, the flow around
the first shortwave will help increase the vorticity advection
associated with the second shortwave, which will pass directly over
Lake Superior and the UP Saturday night. While the NBM brings 30-50
percent chances of snow Saturday morning over the eastern UP, the
more widespread lake enhanced to lake effect snowfall will begin in
earnest Saturday evening. The 00Z LREF gives 80% chances that the
850mb winds will be within 15 degrees of NNW overnight Saturday into
Sunday, though both before and after that time period, more NW winds
appear in the distribution. With temperatures continuing to fall
through Sunday morning (NBM surface lows in the upper teens for the
interior west), plenty of lake-induced instability will be present
and NAM soundings show saturation up to 15kft by around noon on
Sunday, so the forecast bears some monitoring as ingredients are
present for significant snowfall rates, though the wind field will
have a lot to say about the placement of the heaviest snowfall and
uncertainty is too high to place that bullseye with this package.
Soundings show the deep saturation will end from the top down
throughout the evening hours, thus bringing an end to the most
impactful period of snowfall by Monday morning, though enough
instability and moisture will be present to at least keep 30-60
percent chances of snowfall in the forecast through the early
portions of next work week.

Uncertainty then grows into the middle portions of next work week as
the longwave troughing continues to gyrate throughout eastern Canada
and the eastern CONUS, and individual embedded shortwaves will
influence the precipitation forecast. A gradual warming trend is
expected especially late in the week as the ridging over the central
CONUS is expected to encroach into the region in some fashion by
next weekend. The CPC gives over 50 percent chances that the
interior west will see above normal temperatures in the 8-14 day
period, with the rest of the UP in the 40-50 percent range.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 622 AM EST Fri Nov 7 2025

As sfc low pressure kicks east of the UP today, chilly northerly
flow ill usher in lake effect rain showers at all sites this morning
before mixing with snow ~15-18z, earliest at IWD and CMX then SAW.
VFR/MVFR conditions will deteriorate with the increase in lake
effect showers, dipping to IFR with periods of LIFR vis/cigs under
more persistent shra/sn. Gusty N winds increase as well, reaching 15-
25 kts, especially at CMX.

&&

.MARINE...
Issued at 403 AM EST Fri Nov 7 2025

As winds turn northerly today behind a cold front, a brief
period of gales possible (40-60% chance) from the west-central
to east- central parts of the lake. Winds fall back below 20 kts
tonight through Saturday. A deepening low over the southern
Great Lakes and reinforcing cold front will ramp northerly winds
back up Saturday night into early Monday with a few gale force
gusts possible (around 30 percent). The active pattern persists
into next week, though confidence is low in the placement and
timing of individual low pressures and troughs that are capable
of producing gales.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 10 AM this morning to 4 PM EST this
     afternoon for LSZ242>248-263>265.

  Gale Warning from 10 AM this morning to 9 PM EST this evening
     for LSZ249-250-266.

Lake Michigan...
None.

&&

$$

DISCUSSION...GS
AVIATION...BW
MARINE...GS