493
FXUS63 KMQT 080022
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
822 PM EDT Tue Oct 7 2025

.KEY MESSAGES...

- A widespread freeze/frost is expected for inland areas tonight. A
freeze warning and frost advisory have been issued.

- Frost and/or freeze conditions will be possible again Wednesday
night.

&&

.DISCUSSION...
Issued at 251 PM EDT Tue Oct 7 2025

A cold front pushed pushed through the western U.P this morning and
was now located over the central portion of the U.P.  A few light
sprinkles have been reported along the front but no appreciable
precipitation is expected as it continues to push east through the
rest of the U.P this afternoon. Behind the front winds shifted to
the west-northwest and were gusty, especially over the Keweenaw.
Temperatures were in the 50s in the west and low to mid 60s in the
south central and east.

The main challenge with the forecast for tonight is how cold it will
get and coverage of lake effect clouds/showers. A secondary cold
front will drop south through the U.P this evening bringing another
surge of cooler air into the region. 850mb temps will drop to around
-2C resulting in 850mb-lake deltaTs of -15C or so. Clouds will
develop over the lake this evening and deepening inversion heights
to around 7kft should result in scattered lake effect showers. Sub-
cloud dry air will likely limit the precipitation intensity,
however, a convergent wind pattern over central portion of the lake
should help focus a few bands of light showers, mainly east of
Marquette. While the showers will be light and generally not
impactful, lake effect clouds are expected to develop over the
western U.P as well. Some model guidance brings these clouds well
inland, through the interior of the U.P but feel this is a bit
overdone and even a short period of clear skies should allow for
temperatures to plummet over the interior with otherwise optimal
conditions for strong radiational cooling. Kept the temperature
forecast in-line with previous trends and left the frost/freeze
headlines in place.

Temperatures warm into the 50s for Wednesday. Deep mixing and a dry
airmass will bring RH over the interior down as low as 30% but winds
should be light, limiting fire weather concerns.

Wednesday night looks like a good setup for strong radiational
cooling over much of the U.P as winds become calm over much of the
area and a cool, dry airmass remains in place. This should expand
frost and/or freeze conditions closer to the Lake Superior shoreline
and across much of the eastern U.P away from Lake Michigan. Used the
25th percentile of the NBM for overnight lows, bringing many areas
away from the shorelines down into the upper 20s.

The trough axis shifts east of the area late in the week as a ridge
of high pressure builds into the western U.S. This will result in
temperatures warming into the 60s across the U.P late this week into
early next week, several degrees above seasonal averages. A
shortwave will move through the Upper Great Lakes on Thursday night
into Friday under northwest flow aloft. This brings a chance for
precip back into the area but nothing widespread at this time. The
ridge will shift east over the weekend and break down with the
chance for showers coming back into the forecast for late Sunday
into early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 821 PM EDT Tue Oct 7 2025

Northwest winds have tapered off and are no longer an impact with
sustained speeds in the 5 to 10 kt range. Also, VFR will be the
primary flight category, but cannot rule out some brief MVFR at SAW
into tonight as lake effect cloud cover returns. Confidence remains
too low, though, to include mention at this time.

&&

.MARINE...
Issued at 251 PM EDT Tue Oct 7 2025

Northwest winds will gust to 30 knots through this evening over the
central and western portion of the lake as a cold front exits the
area. Expect winds to diminish quickly overnight with light winds
expected for Wednesday. Southerly winds will develop on Thursday
into Friday in response to a low pressure tracking through Ontario.
Winds will increase to 25 kts over the west on Thursday and up to 30
kts lake wide Thursday night. Expect light winds on Friday and
Saturday, generally below 15 kts.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Frost Advisory from midnight tonight to 10 AM EDT Wednesday
     for MIZ001-003-006-007-014-085.

  Freeze Warning from midnight EDT /11 PM CDT/ tonight to 10 AM
     EDT /9 AM CDT/ Wednesday for MIZ002-004-005-009>013-084.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

DISCUSSION...NL
AVIATION...TDUD
MARINE...NL