740
FXUS63 KMQT 041102
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
702 AM EDT Thu Sep 4 2025

.KEY MESSAGES...

- A cool airmass will build over the Upper Great Lakes the rest
  of this week, providing the region below normal temperatures
  all the way to the week`s end.

- There is a 30-70% chance for gales on Lake Superior Friday
  behind a reinforcing cold front, with the highest chances
  along the western side of the Keweenaw. Because of this, a
  Gale Watch has been issued.

- Widespread rain is possible Thursday night into Friday with a
  clipper-like low moving through the region.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 415 AM EDT Thu Sep 4 2025

As the axis of cold air aloft weakens and warm air advection moves a
tad into our area today and tonight, expect the now pure lake effect
rain showers to turn more and more westerly and weaken with time
today, with now most of the interior area trending towards becoming
rain-free as soon as this morning (although the interior west may
see some sprinkles continue throughout the morning hours). The
exceptions to this are the Keweenaw and from M-28 northwards east of
Munising, where the progressively westerly winds will allow for the
lake effect rainfall to continue across these portions of Upper
Michigan. As we move into this evening and the overnight hours,
another Clipper-like low moves through Wisconsin and through the
Straits of Mackinac. As that happens, expect system rainfall to come
over the U.P.. As of right now, it seems like most, if not all of
the area will receive at least of wetting rainfall from this
shortwave low, with several spots potentially getting up to an inch
of liquid before the system leaves Friday; no flooding concerns are
expected as the rainfall rates should be only light to moderate.

While the axis of coldest air will deteriorate a tad today and
tonight (thanks in part to the incoming Clipper-like low), winds
will continue to be gusty over the area today, with westerly winds
gusting up to 30+ mph over the Keweenaw. These gusty winds over Lake
Superior will bring a High Swim risk back over the beaches of Alger
County again today; therefore a Beach Hazard Statement has been
issued as swimming in the lake is expected to be dangerous today.
While there may be some dangerous waves and rip currents that
develop over Marquette County today as well, given the more westerly
wind direction, the threat is not as high (thus only a Moderate Swim
Risk is expected). As the shortwave begins moving through Wisconsin
this evening, expect the winds to begin dying down across the area.
However, once the low starts moving into the Straits late tonight,
expect the winds to begin picking up once again, eventually from the
northwest once more as cold air advection once again starts cycling
back into the area Friday morning.

Overall, expect the temperatures today and tonight to remain below
normal, with lows this morning being in the mid 30s in the interior
areas and low tonight dropping into the lower 40s (warming a little
thanks to the low moving through Wisconsin). As for highs, expect
them to only get up into the 50s for the most part across the area,
save for maybe around 60 in the south central.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 350 PM EDT Wed Sep 3 2025

It will continue to feel much like fall into at least the early
weekend with cool, breezy conditions along with lake affect rain
showers at times. A stronger cliper-like low could bring a round of
widespread rain to the U.P Thursday night into Friday as it moves
through the area.

Thursday night into Friday a clipper-like low will swiftly move
southeast out of Alberta into the the Upper Midwest and Great Lakes
region. Most of the guidance has this low tracking through the
central and eastern U.P with a shield of moderate rain accompanying
it. Rainfall amounts could approach an inch, especially in the
central and west.

Expecting lingering lake effect showers to diminish though the day
on Saturday with dry and cool weather for Sunday. Sunday night looks
to be the best chance for seeing frost over the interior as skies
clear and winds become light. Monday will be see temperatures
moderating into the 60s for most of the U.P.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 702 AM EDT Thu Sep 4 2025

Lake effect rain showers dwindle over the west wind belts today,
leaving conditions generally in VFR during the daylight hours across
the terminals. That being said, some gusty winds are still expected
across the Keweenaw today, with westerly gusts up to 30+ mph being
possible at times. As we move into this evening, expect the winds to
die down as a low pressure begins moving through Wisconsin. As the
low moves from Wisconsin to Ontario tonight, expect light to
occasionally moderate rainfall to move across the area; as this
happens, expect the terminals to drop down to MVFR and IFR.
Northwesterly winds begin to pick up across the U.P. at the end of
the period behind the low, with lake enhanced rainfall starting
back up over the northwest wind belts.

While there is around a 30% chance we could see LLWS over SAW late
tonight due to the low heading towards the Straits of Mackinac
(causing the change in wind direction and speed with height),
confidence is too low at this point to include in the TAFs. As for
CMX and IWD, LLWS chances are less than 10% as model guidance does
not show much wind shear with height up to 2 kft.

&&

.MARINE...
Issued at 436 AM EDT Thu Sep 4 2025

A storm system is brining windy conditions, lake effect rain showers
and the threat for waterspouts over Lake Superior today. Another
period of windy conditions will be possible on Friday. Thereafter,
expecting lighter winds for Saturday night into early next week.

Today, winds will slowly shift to the west and slacken some, falling
below 25kts by late this evening (some gale force gusts up to 35
knots are possible today though over mainly the central and east).
Expecting the waterspout threat to diminish this morning as the low
pressure pushes north away from the lake.

By Friday morning another low pressure will approach the area,
bringing a reinforcing cold front and windy conditions back to the
lake. Expecting northwest to west winds to gust up to 30 kts Friday
through Friday evening over much of the lake, with the central and
east having a moderate (30-70%) chance for seeing gales up to 35
knots; the central lake has the highest chances, whereas the eastern
lake gales look to be fairly quick and transitory as the low lifts
through the Straits into Ontario.

The pressure gradient will begin to weaken Friday night, with most
of the lake falling below 20 kts by Saturday morning (the exception
being near the Keweenaw where gusts to 25 kts will hold on through
the day). For Saturday night through early next week, expecting the
winds to be lighter, below 20 knots.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement through this evening for MIZ006.

Lake Superior...
  Gale Watch from Friday morning through Friday evening for
     LSZ242>247-263>265.

  Gale Watch from Friday morning through Friday afternoon for
     LSZ249-250-266.

  Gale Watch from Friday morning through Friday afternoon for
     LSZ251-267.

Lake Michigan...
  Gale Warning from 2 AM to 11 AM EDT Friday for LMZ221-248-250.

&&

$$

SHORT TERM...TAP
LONG TERM...NL
AVIATION...TAP
MARINE...NL/TAP