271
FXUS63 KMQT 181809
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
209 PM EDT Fri Sep 18 2026

.KEY MESSAGES...

- Chance of rain (30-50%) mainly south of US-2 this evening through
Saturday evening. Chances of 1/3 inch of rain are less than 10% for
all except southern Menominee County.

- Low temperatures in the upper 30s to low 40s tonight for the
eastern U.P. and the central-western U.P. will lead to a 10-25%
chance of frost formation. Those with sensitive outdoor vegetation
may need to consider taking protective action to prevent frost
damage.


- Dry pattern with high pressure sets up Saturday night through much
of next week. Below-average temperatures expected through Wednesday,
giving way to above-normal temperatures late week.

&&

.DISCUSSION...
Issued at 208 PM EDT Fri Sep 18 2026

Current radar reflectivity depicts a large area of stratiform rain
across MN and western WI, which is associated with a shortwave
trough moving across the upper Midwest. As seen in visible satellite
imagery, overcast skies are present across the western CWA, with
cloud cover breaking up into mostly to partly cloudy skies in the
central and eastern U.P.

A generally zonal 500mb pattern has set up across the Great Lakes
this afternoon due to the presence of a deep low pressure center
over northeastern Quebec and Newfoundland and a broad 596 dam over
TX, OK, and AR. Deep troughs are present on either side of this area
of high pressure over northern NV and eastern FL, respectively. A
ridge-riding shortwave continues to make its way across the northern
Midwest, bringing the aforementioned precipitation to MN and WI.
This stratiform rain is expected to continue progressing across the
southern portion of our CWA tonight through Saturday evening.
Accumulation probabilities remain low, with the 12z HREF indicating
a less than 10% chance for 24-hour accumulations to exceed a third
of an inch anywhere in the CWA outside of portions of southern
Menominee county. The 00z LREF continues to be a little more
optimistic, with a 10-20% chance of exceeding a third of an inch for
areas south of US-2. In either case, areas outside of the southern
U.P. are expected to remain mostly dry. With light winds, humid
conditions, and minimum temperatures in the upper 30s to low 40s,
there is a slight chance (10-25%) that some frost formation could
occur in the inland regions of the eastern U.P. and central western
U.P. tonight. Those with sensitive outdoor vegetation may need to
consider taking protective action to prevent frost damage.


The trough associated with the Quebec low progresses eastward on
Sunday while a 500mb ridge is expected to build across the northern
Plains and south-central Canada. South of the ridge, across the
central and southern Plains, a trough is expected to deepen,
creating a split flow pattern. The U.P. is expected to remain under
the northern ridge through Monday morning, keeping the area dry with
seasonably cool temperatures. Uncertainty increases toward the
middle of the week, as ensemble spread increase. However, the latest
CPC temperature and precipitation outlooks over next the 14 days
indicate warmer and possibly drier than normal conditions.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 203 PM EDT Fri Sep 18 2026

Low pressure moving through MN/WI will bring widespread high level
cloudiness to the U.P. through tonight with cigs eventually falling
to around 10kft as deeper moisture pushes into the area. Much of the
rainfall associated with the system will struggle to make it north
into the U.P. where low level dry air was in place. IWD will be
closest to the deeper moisture with MVFR cigs expected to develop on
Saturday around noon. Expect mainly light easterly winds, becoming
southeast tonight.

&&

.MARINE...
Issued at 208 PM EDT Fri Sep 18 2026

Lake Superior: This afternoon though tonight, winds will remain
easterly at 15-20kts. On Saturday morning, winds are expected to
shift from easterly to southeasterly, before returning to easterly
for the eastern portion of the lake and shifting to northeasterly
for the western arm in the early afternoon. Outside of the southern
portion of the western arm, which could reach over 20kts, winds are
expected to remain at or below 15kts. Sunday, northeasterly flow
over lake increases in strength up to 25-30kts across the lake. The
western arm and south-central portion of the lake could see gale-
force gusts up to 35kts. Currently, the HREF and NBM are not
predicting gale conditions, however localized channeling could
result in higher wind speeds. Winds are expected to shift easterly
and reduce to 20kts or below for areas outside of the souther half
of the western arm (where speeds up to 30kts are possible) Monday,
continuing through Tuesday. Wave heights are expected to remain
below 2ft until Sunday morning, when they build to 3-5ft, with
higher wave possible in the southern portion of the western arm.
Wave heights reduce to 2-4ft Monday, falling to 1-2ft Tuesday.


Northern Green Bay and Northwestern Lake Michigan: This afternoon
through tonight, winds will be easterly around 10kts. On Saturday,
expect easterly winds around 15kts with wave heights around 1ft. On
Sunday, winds shift to northeasterly at around 20kts with wave
heights around 2ft. Sunday night into Monday, winds increase up to
25kts, with wave heights up to 3-4ft. Monday through Tuesday, wind
shift back to easterly at around 20kts with height up to 2-3ft.

&&

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

&&

$$

DISCUSSION...LH
AVIATION...NL
MARINE...LH