541
FXUS63 KMQT 061120
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
720 AM EDT Sun Sep 6 2026

.KEY MESSAGES...

- Patchy fog in the central and east this morning could be dense
  at times, reducing visibility down to 1/4 mile (30% chance).

- Above-average temperatures and dry weather persists through
  Labor Day Weekend, with high temperatures in the mid 70s to
  low 80s.

- A low pressure system tracking to the north early next week
  brings rain chances on Tuesday and breezy winds Tuesday and
  Wednesday.

- Frequent westerly wind gusts of 20 to 30 mph are expected on Wednesday.
  There is a 25-50% chance for gusts up to 40 mph near Lake
  Superior and 50-70% chance for gusts up to 45 mph in the
  Keweenaw. West gales of 35+ knots are becoming increasingly
  likely for Lake Superior.

&&

.DISCUSSION...
Issued at 257 AM EDT Sun Sep 6 2026

Early this morning GOES water vapor imagery and model 500mb height
analysis showed an upper level ridge remaining in place over the
central U.S. extending north into the Canadian Prairies. Downstream
of the ridge, weak instability in northwest flow aloft had resulted
in a few sprinkles over the far western U.P. and passing mid-level
cloudiness. Elsewhere skies were clear with light winds supporting
strong radiational cooling. This has resulted in temperatures
falling into the 40s and 50s away from the lakeshores along
with patchy dense fog developing. Close to the Great Lakes it
was much warmer with temperatures in the low 60s.

After some patchy morning fog, a warm and pleasant Labor Day
Weekend will continue with surface high pressure over Ontario
extending a ridge south into the U.P. This will keep a weak
pressure gradient and light winds across the U.P. through Labor
Day. With weak flow and diurnal heating expect a lake breeze to
develop off of the Great Lakes in the afternoons keeping
temperatures a bit cooler near the shorelines (but still warm,
low 70s). Inland temperatures will warm well into the 70s to
mid-80s, 10 to 15 degrees above average. Tonight will be a bit
warmer than Saturday night as high level cloudiness increases
with temperatures falling into the low 50s inland and near 60
lakeside. This should limit fog formation with NBM probabilities
generally < 15% for fog development.

As the upper level ridge shifts east and troughing deepens over
the Plains, southerly flow increases cloud cover on Monday and
continues the warming trend for overnight lows. Temps settle
into the mid 50s to mid 60s Monday night and upper 50s to 60s
Tuesday night.

Precip chances return Monday night from the west, continuing into
Tuesday night as the upper level ridge moves east over the Great
Lakes and flattens. This gives way to the deep western trough to
lift northeast to Manitoba by Tuesday afternoon, which then tracks
east to Quebec through Wednesday. A resulting sfc low from the
northern Rockies lifts to Manitoba for Tuesday, then moves across
far northern Ontario to Quebec through Wednesday. Showers return to
the UP ahead of the associated cold front, mainly on Tuesday.
Instability struggling to reach 500 j/kg mean strong to severe
storms are not expected. Widespread rainfall amounts have trended
down as deterministic solutions are indicating QPF splits somewhat
around the UP. Probabilities of at least 1 inch of rain in 24 hours
are now 30-60% only over the north half and far western Upper
Peninsula, quickly falling to 10-25% elsewhere. This system also
yields breezy winds. Initially expecting south winds on Tuesday
ahead of the cold front gusting between 15-30 mph, particulary in
ideal southerly downslope flow. Behind the front, pressure rises and
CAA support stronger westerly winds on Wednesday with frequent gusts
of 20-30 mph. Probabilities for gusts exceeding 40 mph are between
25-50% from Marquette to Whitefish point and Saxon Harbor to
Ontonagon. Could see a Wind Advisory being needed in the Keweenaw
where probabilities for gusts exceeding 45 mph already are between
50-70%.

Weak high pressure ridging returning to the area bring back much
calmer conditions on Thursday. The drying trend in the forecast has
also removed lingering precip chances until the weekend, although
the marginally cold enough 850 mb temps could yield scattered lake
effect cloud cover late Wednesday night into Thursday. Otherwise
temps return near normal in the upper 60s to mid 70s late next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 720 AM EDT Sun Sep 6 2026

Fog will impact CMX with VLIFR conditions to the start of the TAF
period. Fog should dissipate after sunrise, clearing
out by 13z. Thereafter expect VFR conditions along with light
winds through the remainder of the TAF period with high pressure in
control.

&&

.MARINE...
Issued at 356 PM EDT Sat Sep 5 2026

Lake Superior: High pressure influence keeps winds below 20 kts
through early Monday afternoon. A more prominent system lifting to
the north of Lake Superior Monday night through Wednesday brings a
prolonged period of widespread 20 to 30 kt winds. Best chances for
gales to 35 kts (40 to 80% chance, highest near the Keweenaw) are
Wednesday behind the cold front, supported by pressure rises. There
is a low (20 to 40%) chance for southerly warm air advection gales
on Tuesday and a 20 to 50% chance for high end gales (40 kts or
higher) near the Keweenaw on Wednesday. Winds settle below 20 kts by
Thursday afternoon. Another system traveling north of Lake Superior
brings stronger wind potential into early next weekend, but
significant model discrepancies leave confidence low.

Northern Green Bay and northwestern Lake Michigan: Winds remain 15
kts or lower through Labor Day as high pressure slowly builds
overhead. A more prominent system lifting north of the region early
next week increases winds to around 15 kts with gusts up to 20 to 30
kts Tuesday afternoon through Wednesday. Winds settle below 20 kts b
Thursday morning, holding below 20 kts into Friday. Another system
traveling north of Lake Superior brings stronger wind potential into
early next weekend, but significant model discrepancies leave
confidence low.

&&

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

&&

$$

DISCUSSION...77/NL
AVIATION...NL
MARINE...77