246
FXUS63 KMQT 231306
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
906 AM EDT Sat Aug 23 2025

.KEY MESSAGES...

- A seasonably strong system moving north of the Great Lakes
  will bring hazardous marine conditions to Lake Superior this
  weekend; gales up to 35 knots are possible (20 to 40% chance).

- Cooler than normal temperatures and lake enhanced to lake
  effect rain showers are projected to return this weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 455 AM EDT Sat Aug 23 2025

MQT radar mosaic has quieted down significantly over the last
few hours after an uptick earlier this morning. Currently, a few
rain showers are still drifting from west to east across the
central portions of the forecast area after some thunderstorms
over the western third. Water vapor imagery/surface analysis
this morning still shows low pressure over central Ontario with
its associated cold front pushing through the U.P. This cold
front will be responsible for some Fall like weather today with
cooler temperatures than we`ve been experiencing most of the
summer. Daytime highs across the area are expected to only top
off in the mid to upper 60s across the west and Keweenaw to low
70s over the south and east. In addition, northwest winds will
be strong across much of the U.P. with sustained speeds of 10 to
15 mph and gusts to 20 to 25 mph. The Keweenaw will be
especially impacted with gusts climbing into the 30 to 35 mph
range. Tonight, while lake enhanced cloud cover will help to
inhibit radiational cooling, overnight lows are still projected
to dip into the upper 40s across the interior west with low to
mid 50s across the remainder of Upper Michigan. In addition, a
weak shortwave in the mid-level flow will need to be monitored
after Sun 06Z for weak shower/thunderstorm development. For now,
will only carry a 30-40% chance.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 415 PM EDT Fri Aug 22 2025

The mid level trough will be positioned over N Ontario and James Bay
with a embedded shortwave pivoting directly overhead starting Sun
morning. A high pressure resides well to the SW over the four
corners, extending a mid level ridge into the PAC NW. A 994mb low
will have made it to James Bay at this point with high pressure over
the Canadian Prairie extending into the Plains. As a result, cold NW
flow will be parked over the UP with 850mb temps settling to ~3C by
the end of the day; Lake Superior waters currently are averaging
~17C, yielding delta-Ts of 13-15C. Given the strong lift, buoyancy
present and ample low level moisture noted in model soundings up to
10 kft, lake effect SHRA are expected across the NW wind belts. As
high pressure and an associated drier airmass continues to creep
over the CWA and lift weakens, coverage of SHRA should lessen, but
supportive delta-ts for lake effect -SHRA should continue through
Mon. This seasonably cold airmass yields below normal temps with
highs in the mid 50s to mid 60s and lows in the 40s to low 50s. If
cloud cover/SHRA are able to clear out better, temps dipping into
the 30s are possible. Meanwhile, breezy NW winds of 10-20 mph are
expected on Sun, particularly in the Keweenaw where gusts up to 30-
35 mph are likely. These tapper down slightly overnight, but return
elevated in the 10-25 mph range for Mon.

After the start of the work week, a drier pattern is favored as
cyclonic flow continues to weaken and sfc high pressure shifts to
the Mid MS Valley. Temps warm slightly into the 60s for Tue and
upper 60s to mid 70s for Wed. A much weaker mid level trough quickly
descends over Manitoba and Ontario on Wed and over the Great Lakes
Wed night. An associated sfc trough and cold front look to accompany
this, bringing back a around of SHRA to the region Wed night/Thu.
Confidence in the fcst quickly breaks down into the weekend as the
mid level ridge to the W falls apart. Left the NBM dry PoPs after
Mon given the uncertainty, but some PoPs could be added with future
fcst packages as time progresses and better model agreement is
achieved.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 906 AM EDT Sat Aug 23 2025

13z UPDATE...Lake-induced clouds have developed quicker than
previously anticipated over the western terminals. Thus, BKN MVFR
cigs are expected to continue for at least the next few hours for
IWD and CMX, with MVFR cigs looking to continue for the rest of
today over IWD (this is possible for CMX too, but there is higher
uncertainty of that occurring over there at this time, so I kept the
going forecast from 16z onwards).

Mainly VFR conditions for the duration of the TAF period. However,
cannot rule out a period of MVFR cigs in the Sat 14-18Z time frame
at CMX and IWD, but confidence is not high enough to leave mention
in at this time. The main impact will be the strong northwest winds,
which will be sustained in the 12 to 15 kt range, gusting to 20 kts
at IWD/SAW and 30 kts at CMX. Winds finally begin to calm down by
late evening.

&&

.MARINE...
Issued at 415 PM EDT Fri Aug 22 2025

Southwest winds across the lake, up to 20 kts over the west half,
continue through this evening as a cold front approaches. A
disturbance moving over the Upper Great lakes will continue to bring
showers and storms across the lake, with some of the storms
potentially bringing gusty, erratic winds and small hail to the sfc.
Winds shift west-northwest tonight into Sat as the cold front
crosses the lake, increasing to 20-30 kts for Sat. A few gale force
gusts up to 35 kts are possible (20-40% chance).

Continued cold air advection behind the cold front through the
weekend keep the northwest winds elevated across the lake around 15-
30 kts through Sun night and between 15-25 kts on Mon. Low chances
for gales briefly return on Sun (10-30% chance over the east). Winds
fall below 20 kts by Tue as ridging builds in over the region.

&&

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

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...TDUD
LONG TERM...Jablonski
AVIATION...TAP/TDUD
MARINE...Jablonski