338
FXUS63 KMQT 191136
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
736 AM EDT Sat Sep 19 2026

.KEY MESSAGES...

- Chance of light rain (30-50%) mainly south of US-2 through this
evening. Chances of 1/4 inch of rain are less than 10% for all
except the Menominee area.

- Sunday, light lake-enhanced showers will be possible (30-50%)
especially along the terrain of the western and north-central UP.
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 344 AM EDT Sat Sep 19 2026

Early morning GOES-East Nighttime Microphysics RGB imagery shows
deep clouds associated with a disturbance remaining mostly over
Wisconsin, though the MNM METAR does show BKN028 at 0645Z.
Elsewhere, fair-weather clouds or clear conditions are observed.
KMQT radar shows the UP clear of precipitation as of 07Z but some
scattered weak reflectivities have been observed just over the state
line from Gogebic County as well as widespread weak reflectivities a
county or two from Menominee County and moving east-northeast.
Recent CAMs have been a bit more aggressive in bringing very light
showers across much of the central UP today, but with the best
forcing for showers well to the south, will keep PoPs and QPF low
for this forecast package. A slight upwards trend in the temperature
forecast for this morning has resulted in this forecast trimming
back the frost potential to just some patches of the eastern third
of the UP, so no frost advisory will be issued.

The 500mb pattern consists of 595 dam ridging over northeast TX
bounded by deep troughs centered over Idaho, Florida, and Hudson
Bay. A ridge-riding shortwave over the WI/IL state line is causing
the aforementioned disturbed weather to the south. While models have
long-since trended precipitation with that disturbance primarily
south of the UP, the Hudson trough will pass a weak cold front
across the region for Sunday. 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 UP being enough to force weak precipitation. Thus, some
light PoPs and a couple hundredths of an inch of QPF have been added
for the north/western UP for Sunday. This will also come with some
gustier NE winds, with gusts of 20+ MPH forecast especially along
the Lake Superior shores. This will also drive waves of 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. The NBM reintroduces PoPs to the forecast late next Saturday,
but that might be down to ensemble chaos more than an actual precip
signal. 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, which will lead to cool conditions at 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 /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 734 AM EDT Sat Sep 19 2026

VFR conditions will prevail for most of today. The exception
will be a weak low pressure system moving south of the UP
bringing a chance at MVFR cigs at IWD by early afternoon. Then
MVFR will become likely tonight at IWD and CMX. Meanwhile, winds
will generally be easterly at 5 to 10 kts.

&&

.MARINE...
Issued at 344 AM EDT Sat Sep 19 2026

Through today, 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. Waves increase to near 3 feet over northern Lake Michigan
and Green Bay by Monday as well due to prolonged easterly flow
approaching 20 kt. 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
AVIATION...TDUD
MARINE...GS