136
FXUS63 KMQT 080659
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
259 AM EDT Wed Oct 8 2025

.KEY MESSAGES...

- Frost and/or freeze conditions will be possible tonight for
  inland areas of Upper Michigan.

- Primarily dry conditions prevail until Thursday night and Friday.

&&

.DISCUSSION...
Issued at 258 AM EDT Wed Oct 8 2025

Mostly clear conditions have been observed across Upper Michigan,
save for isolated to scattered lake effect clouds pressing southeast
within northwest flow moving into the associated favored locations
of the Keweenaw and central and eastern Upper Michigan. Light radar
returns have been observed and some light rain may occasionally be
reaching the ground, including here at NWS Marquette, which observed
0.01 inches of rain between 1 and 2am EDT. The cloud cover has been
wreaking havoc on temperatures. For example, our office was
observing 34 degrees and then warmed to 41 very quickly as a shower
moved overhead. This same trend is being observed elsewhere, where
cloud cover is hindering significant cooling or resulting in warming
at times. Elsewhere, light winds and dry air have allowed overnight
temperatures to plummet into the 20s and 30s interior central.

For the remainder of this overnight period, off and on lake effect
showers/clouds will move through central and eastern Upper Michigan
and the Keweenaw. These clouds may continue to prevent significant
cooling near the Lake Superior lakeshores, but interior locations
should continue cooling. Widespread upper 20s or low 30s are on
track for most interior locations by sunrise. Those moderated by the
Great Lakes or cloud cover may only dip into the low 40s.

Dry conditions prevail today and Thursday as mid-level ridging
inches eastward into the forecast area and a surface high transits
Upper Michigan. Light warm air advection between the days will
result in a slight warming trend, with today peaking in the mid to
upper 50s for most and Thursday in the low to mid 60s. Tonight the
transiting high will result in continued light winds, plenty of
subsidence, and the dry airmass, providing another night of
effective radiational cooling. Occasional lake effect cloud cover
may move over the east, but this should be limited by the
transiting high. Opted to follow the theme in the previous forecast
package, bringing widespread upper 20s to low 30s for most areas
removed from the lakeshores. 30s still look good for the most
lakeshore communities too. Since we currently have Freeze Warnings
and Frost Advisories out, will hold off on issuing freeze/frost
headlines in this forecast cycle. Thursday may be a little breezy as
well, with widespread 15-20 mph southwest winds, potentially higher
in downslope prone locations along the Lake Superior lakeshore.

Thursday night, a sharp shortwave/upper level low will dive
southeast through Manitoba into Ontario. As it reaches Lake Superior
and Upper Michigan on Friday, a surface low will develop along the
eastern lakeshores followed by the pair continuing southeast into
the lower Great Lakes Saturday/Sunday. The system will pull a weak
cold front through the region which will be the focus for the
developing surface low. This will help support scattered rain shower
activity Thursday night into Friday morning across the west and
Friday into Friday evening in the east.

Mid-level ridging builds in afterwards, stretching atop the
departing closed low and spanning much of middle CONUS. The
departing system may interact with a tropical system in the eastern
Atlantic, eventually resulting in a closed low hovering along the
east coast into next week. Upstream, another shortwave lifts
northeast along the ridge`s western periphery, which brings the next
chance of rain showers in the late Sunday/Monday timeframe.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 124 AM EDT Wed Oct 8 2025

VFR will be the primary flight category, but cannot rule out some
brief MVFR at SAW early this morning as lake effect cloud cover
returns. Confidence remains too low, though, to include mention at
this time. Northwesterly winds will be light in the 4 to 8 kt range.

&&

.MARINE...
Issued at 258 AM EDT Wed Oct 8 2025

Winds are coming down over Lake Superior, but at the time of this
writing, a handful of northerly or northeasterly wind observations
are still occuring over eastern Lake Superior, specifically STDM4
blowing ~25kts and the James R. Barker observed 19kts at 6z northeast
of the STDM4. As high pressure slides into the region today, winds
should continue lightening, largely remaining below 20kts through
tonight. Thursday, an upstream cold front will press closer to the
region as the high departs to the south and east. This will support
increasing southwesterly to southerly winds through the day to near
25kts. Thursday night when the front is moving into the region,
these winds increase to near 30kts. Some guidance suggests the
potential for low end gales, namely the GFS and EC. The latter`s
ensemble system currently suggests ~30% for gales across parts of
western and eastern Lake Superior, which is an upward trend. Will
need to monitor this for consistency in the next few days. After
this system exits Friday, northwest winds shift to northeasterlies
as the departing system begins stalling and interacting with a
potential tropical off the east coast, and another wave approaches
from the west. During this period, primarily winds below 20kts
should prevail. By Sunday, the upstream system moves closer to the
region, resulting in southeasterlies increasing to near 25-30kts.
These elevated winds gradually subside Monday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Frost Advisory until 10 AM EDT this morning for MIZ001-003-006-
     007-014-085.

  Freeze Warning until 10 AM EDT /9 AM CDT/ this morning for
     MIZ002-004-005-009>013-084.

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

&&

$$

DISCUSSION...JTP
AVIATION...TDUD
MARINE...JTP