773
FXUS63 KMQT 202311
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
711 PM EDT Sun Sep 20 2026

.KEY MESSAGES...

- Dry pattern with persistent high pressure sets up through much
  of next week. Below-average temperatures through Wednesday
  (including morning frost potential), gives way to above-normal
  temperatures late week.

&&

.DISCUSSION...
Issued at 144 PM EDT Sun Sep 20 2026

Early afternoon GOES WV imagery and RAP analysis show a cut-off low
over WY, shifting east toward Northern Plains. Further upstream
there is a ridge over the Pacific Northwest and a trough off the
coast of CA. High pressure of 1027 mb has become centered over
northwestern Ontario with a cold front now south of the UP. Low
level cloud cover is beginning to decrease in coverage as drier air
filters in and 850 mb temps marginally warm up ~1-2C, but stubborn
scattered clouds persist in the west into tonight. This helps keep
afternoon highs cooler than normal in the mid 50s to mid 60s. Breezy
northeast winds, particularly near Lake superior where gusts of 20-
30 mph have been observed, taper off through this evening as the
pressure gradient weakens and the shallow inversion develops. This
supports a high swim risk along Lake Superior shores into tonight,
possibly into early Monday morning for Marquette County. When low
clouds clear out, mid to high level clouds take over for tonight
courtesy of the western cut-off low which breaks up as it moves east
over the northern Plains. Although this is not an ideal radiative
cooling set up, 5-10 degrees colder than normal lows are expected
with 30s for the interior and low to mid 40s near the Great Lakes
shores. Patchy frost is possible (10-20% chance), but opting for no
headlines given limited coverage and low confidence.

Although high pressure continues to strengthen through the middle of
the week over Quebec, extending ridging over the Great Lakes, the
upper level troughing moving east over the Midwest supports mostly
cloudy skies through Monday before clear skies return Tuesday
through Wednesday night. The split flow that sets up over eastern
Canada/CONUS helps this high pressure persist into the weekend,
possibly keeping dry weather until early next week. That said, the
NBM currently has low PoPs between 15-24% returning on Sunday. The
cooler temps gradually trend to above normal by the weekend as
southerly flow returns. Decreasing cloud cover and lighter winds
yields better frost potential Monday night (20-60% chance in the
interior, highest west). Tuesday night could also bring patchy frost
to the interior (10-40% chance).

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 711 PM EDT Sun Sep 20 2026

VFR conditions are present save for SAW at MVFR at the start of the
00z TAF period. SAW should lift to VFR within the next few hours as
diurnal cu wanes. Light winds and mostly clear skies expected
overnight into Monday.

&&

.MARINE...
Issued at 144 PM EDT Sun Sep 20 2026

Building high pressure to the north tapers off northeast winds
mainly below 20 kts this evening, save for gusts in the low 20 kt
range over northern Lake Michigan and the southeastern waters of
Lake Superior tonight. Significant wave heights on Lake Superior,
especially in the south and west, between 4-7 ft this afternoon fall
to ~4 ft or lower for tonight. Waves in the northern Bay of Green
Bay and northern Lake Michigan linger between 1-4 ft through mid
next week given persistent northeast to east flow is expected. Winds
become easterly for Monday as the high strengthens over Quebec.
Aside from northeast winds channeling in the far western nearshores
of Lake Superior, yielding gusts up to 25 kts, winds lakewide
primarily hold below 20 kts. High pressure remains dominant through
the forecast, keeping the pressure gradient weak and winds largely
20 kts or less.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 8 PM EDT this evening for MIZ005-
     006.

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

&&

$$

DISCUSSION...77
AVIATION...BW
MARINE...77