Wallace, Michigan Weather Forecast Discussion

845
FXUS63 KMQT 191124
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
724 AM EDT Fri Sep 19 2025
.KEY MESSAGES...
- Isolated to scattered showers and thunderstorms today across
  western Upper Michigan.
- Off and on showers and thunderstorms are expected Saturday
  through early next week.
- Seasonable temperatures continue through next week.
&&
.DISCUSSION...
Issued at 343 AM EDT Fri Sep 19 2025
Early morning GOES WV imagery and RAP analysis highlight an ill-
defined closed low over the N Plains with several shortwaves
rotating around it. At the sfc, a weak 1013mb sfc low resides over E
SD, and includes a complex array of frontal boundaries extending
across the midwest; all of which remain to the SW of the CWA. With
the loss of diurnal instability and weak forcing present, ongoing
-shra have been sparse, but low chances (~15-30%) will continue with
the support of a subtle LLJ/shortwave pair over the W into this
morning with up to 0.25" possible. Otherwise temps settle into the
50s ahead of sunrise. Slight chance PoPs over the W diminish into
the afternoon hours as forcing departs. Steady E winds around 10 mph
with gusts to 15-20 mph are expected with up to 30 mph in the
Keweenaw. This will keep areas near Lake Superior cooler with
generally cooler highs this afternoon in the upper 50s to upper 60s.
Tonight through Sat, the closed low unravels as it approaches the
Great Lakes and the deeper shortwave currently over IA tracks toward
the UP. The lifting shortwave and then an additional trailing wave
on Sun results in an gradual uptick in -shra activity, with the peak
coverage occuring Sat night and Sun. Meanwhile another trough makes
landfall over the PAC NW on Sun. Some rumbles of thunder can`t be
ruled out on Sat, but strong to severe storms are not expected given
the limited instability during this period. Better instability is
present (200-800J/kg MUCAPE) with the secondary shortwave on Sun,
but bulk shear is questionable. Despite instability further
increasing for Mon, shear and forcing are even more questionable.
From there, high pressure builds in with diminishing cyclonic flow
aloft bringing back drier weather for the mid to late portion of the
work week. Confidence in the fcst rapidly breaks down at this point
as the aforementioned trough making landfall over the PAC NW on Sun
is not resolved well beyond Wed. A ridge looks to build in over the
W in the trough`s wake, traversing E toward the Canadian Prairie late
week. How that feature gets affected by a closed low developing
somewhere over the Central U.S. or several messy shortwaves across
the CONUS is not clear. Opted to leave the NBM as is, favoring drier
weather and rather steady temps with highs in the mid 60s to low 70s
and lows in the mid 40s to mid 50s.
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 724 AM EDT Fri Sep 19 2025
Upper level low to our west with multiple waves rotating within its
circulation will support rain showers at KIWD today and cloud cover
at all sites. Rain showers mixed with IFR and MVFR ceilings at KIWD
will improve this afternoon as a break in the rainfall occurs, but
could return overnight as the next wave moves close to the region.
Easterly winds increase today at KCMX, potentially building to 30kts
by afternoon. These are expected to lighten overnight. Lighter winds
are expected at KSAW, but will vary between northeasterly and
easterly through the day.
&&
.MARINE...
Issued at 343 AM EDT Fri Sep 19 2025
NE winds of 15-25 kts across the lake this morning increase to ENE
20-30 kts over the W half of the lake by this afternoon; there is a
20-40% chance of gale force gusts to 35 kts over the far W third of
the lake. Channeling likely will support more frequent gusts into
gale territory when approaching the Duluth harbor. This builds
significant wave heights up to 3-4 ft SW of Stannard Rock and
between 4-9 ft over the W half this afternoon and evening. Winds
veer ESE tonight into early Sat with gusts continuing to 20-30 kts,
this time strongest winds will be over the E half of the lake. This
results in waves of 3-6 ft over the N-Central waters and along the
international border on Sat. Winds gradually settle below 20 kts
from W to E late in the day Sat through Sun morning, likely
remaining below 20 kts through much of next week. Otherwise, expect
on and off showers and thunderstorms this weekend.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
DISCUSSION...Jablonski
AVIATION...JTP
MARINE...Jablonski

NWS MQT Office Area Forecast Discussion