641
FXUS63 KMQT 040815
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
415 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 /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1259 AM EDT Thu Sep 4 2025

Off and on lake effect rain showers are expected in this TAF period,
mainly at KCMX tonight, and again Thursday afternoon. MVFR
conditions are expected in these showers. Gusty winds near 20kts are
possible tonight at KCMX. Increased mixing Thursday will support
gusty winds near 20kts at KIWD/KSAW and near 30kts at KCMX.

&&

.MARINE...
Issued at 350 PM EDT Wed Sep 3 2025

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

A tight pressure gradient will remain over Lake Superior tonight
resulting in near-gale force northwest winds over the central
portion of the lake with gales likely along and north of the
Keweenaw through early evening. On Thursday winds will slowly shift
to the west and slacken some, falling below 25kts by late Thursday
evening. Expecting the waterspout threat to diminish Thursday
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 winds to gust up to 30 kts Friday trough
Friday evening over much of the lake. The strongest winds again
appear to be along and north of the Keweenaw where the NBM has 40-
60% chance for winds exceeding gale force.

The pressure gradient will begin to weaken toward Saturday morning
with most of the lake falling below 20 kts except 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...JTP
MARINE...NL