905
FXUS63 KMQT 200507
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
107 AM EDT Sun Sep 20 2026

.KEY MESSAGES...

- Spotty, light rain showers continue to graze the southern UP
through this evening. Rain totals below 0.10in are expected.

- Light lake-enhanced showers will be possible (30-50%) especially
along the terrain of the western and north-central UP Sunday. Gusty
northeast winds will cause potentially hazardous swimming conditions
and rip current risks along Lake Superior.

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

&&

.DISCUSSION...
Issued at 306 PM EDT Sat Sep 19 2026

Early afternoon RAP analysis and water vapor imagery reveal midlevel
ridging moving towards the central Mississippi valley, with midlevel
lows closing off over southern Idaho, Florida, and Hudson Bay. A
shortwave trough is swinging southeast of the latter feature into
Ontario. At the surface, broad low pressure is stretched out from
Kansas northeastward into IA, with resulting WAA into WI touching
off light rain showers particularly over the southern portions of
the state. Still, some light rain showers have been able to make it
into the south-central UP. These could drop a couple hundredths of
an inch of rain mainly over Menominee and Delta county through the
rest of the afternoon, but significant impacts are not expected apart
from persistent cloudiness across the UP. In spite of the cloud
cover, temperatures across the area are climbing comfortably into
the mid 60s for most, with some spots even flirting with the upper
60s.

Tonight, a cold front associated with the Ontario trough drops
southeastward over Lake Superior and into the UP. This may bring
some spotty rain showers to the western and central UP, but they
will have to contend with dry midlevel air...and will note that most
of the CAMs show these dying out soon  upon reaching our shores.
Into the daytime hours, a surge of cooler air aloft will cause
marginally-supportive thermodynamic profiles for some lake-enhanced
or lake-effect rainfall, with CAMs showing the orographic forcing of
the western and north-central UP being enough to force weak
precipitation. Thus, will maintain chance pops and another couple
hundreds of QPF. This will also come with some gustier NE winds,
with gusts of 20+ MPH forecast especially along the Lake Superior
shores. This in turn cranks wave heights up to 6 ft within 5 miles
of the Lake Superior shoreline, which will drastically increase the
risk of hazardous rip currents and challenging swimming conditions
for those trying to squeeze in a late-September Sunday beach day at
Lake Superior beaches.

In the wake of the weekend disturbances, the western CONUS trough
will shift over the Dakotas by Sunday, weakening slightly. At the
same time, ridging to the north of the trough amplifies, causing
split flow. This results in dominant surface high pressure
establishing over northern Ontario and Quebec through much of next
week, likely bringing an extended period of dry weather to the UP.
The latest NBM keeps us dry even through next weekend as ensembles
flip-flop on whether ridging will persist over the region. Upstream
ridging aloft results in cooler continental flow aloft, and being on
the south/southwest periphery of a surface high results in cool
easterly to northeasterly flow at the surface off of the Canadian
Shield. This brings cool conditions for the beginning of the week
with a gradual warming trend as the week goes on. For instance, the
NBM even calls for up to 50% chances of sub-freezing temperatures
for Tuesday morning, though the LREF chances are significantly
lower. By the end of the week, NBM highs are widespread 70+. The CPC
6-10 and 8-14 day outlooks both show 50+% chances for the UP to be
in above average temperatures for the end of September and a slight
favoring of below normal precipitation (30-40% chance).

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 107 AM EDT Sun Sep 20 2026

VFR/MVFR cigs present early this morning deteriorate to MVFR/IFR at
IWD/SAW as a cold front sweeps across Lake Superior through day
break. Given NE upslope flow, cant rule out a few showers or drizzle
at SAW, thus have introduced prob 30s for -shra between ~12-15z.
Conditions improve to MVFR/VFR through the late morning to afternoon
as drier air works into the area. Otherwise, breezy NE winds 15-25
kts are expected at all sites behind the frontal passage.

&&

.MARINE...
Issued at 306 PM EDT Sat Sep 19 2026

This afternoon and evening, weak low pressure to the south and
departing high pressure to the northeast will keep wind gusts
largely below 20 kt. A stronger high building to the north on Sunday
in addition to gusty winds mixing down in the wake of a Hudson Bay
cold front looks to bring 20-30 kt northeast gusts to most of Lake
Superior. Waves across Lake Superior (especially in the south and
the west) build to 4-6 ft. Northeast wind gusts to 20-25 kt will
develop over Lake Michigan by Sunday afternoon as well, with wave
heights building to 2-3ft. Winds slowly fall back to near or below
20kts Sunday night. For the beginning of next week, high pressure
building over Northern Ontario opposing low pressure over the Lower
Mississippi Valley will drive some gradient wind gusts to around 20
kt out of the east before model spread and forecast uncertainty
increases late in the week.

&&

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

&&

$$

DISCUSSION...GS/LC
AVIATION...BW
MARINE...GS/LC