Thompson, Michigan Weather Forecast Discussion

495
FXUS63 KMQT 231122
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
722 AM EDT Tue Sep 23 2025
.KEY MESSAGES...
- Patchy dense fog continues this morning, reducing visibility
  down to 1/4 mile at times.
- Isolated showers today through Wednesday.
- Seasonable temperatures continue through the end of the week.
&&
.DISCUSSION...
Issued at 435 AM EDT Tue Sep 23 2025
Early morning GOES WV imagery and RAP analysis indicate an unsettled
pattern across the N American continent with many trough features
from over S CA, much of the central CONUS, the Great Lakes, and NE
Canada. Also a ridge is noted building over the NW CONUS. The
shortwave directly over the CWA and it`s partner wave just N of Lake
Superior this morning will be the primary drivers of weather in the
short term. Later this week, the evolution of the trough over the
Plains and the overhead shortwaves drive a sfc low over the Lower
Great Lakes. This unsettled pattern in our region continues into the
weekend as two troughs quickly progress E over Canada, sending sfc
troughs and cold fronts overhead before high pressure returns.
This morning, sfc obs for the most part are at their Tds in the 50s.
The saturation along with yesterday`s rainfall supporting ample low
level moisture, the slow increasing cloud cover (parts of the
interior W are still clear as of now), and calm winds has yielded
fog development across much of the UP. Dense fog has been more widely
observed along the W spine where a Dense Fog Advisory was hoisted
early, but patchy dense fog is expected in pockets elsewhere
impacting the morning commute. The current radar mosaic has pretty
much cleared out, but ongoing shra over E Lake Superior likely will
help develop a fog bank which is anticipated to settle S this
morning. The timing of that feature is less certain, but would
impact Marquette and E. Be sure to take it slow and to have your low-
beam headlights on if traveling through fog this morning.
As the two shortwaves rotate over the Upper Great Lakes, isolated
shra are expected through Wed. With limited instability and low
shear, a few rumbles of thunder are possible today. Otherwise, these
will be low impact with a few hundreths being the high end QPF
supported by N upslope flow. Highs today and Wed will be in the 60s
to low 70s with lows in the 50s tonight; additional patchy fog is
likely tonight, but not as dense given slightly higher winds. Lows
Wed night will be in the 40s to low 50s.
The positively tilted trough over the Plains begins it`s E track
tonight, interacting with the Great Lakes shortwaves Wed night
onward. Surprisingly, the NAM/ECMWF are in agreement with a more
vigorous shortwave quickly passing from the Plains energy to the
Great Lakes circulation on Wed. This ends up with a sfc low tracking
from S IL at 1006mb to S Ontario at 999mb, almost 10mb deeper of a
low than the Canadian/GFS (also more N track). Regardless, the bulk
of the associated precip looks to remain SE of the CWA. Where the
uncertainty does leave wiggle room in the fcst is the expected temps
and strength of winds during the period (low impacts). For now
expect highs on Thu in the upper 60s to mid 70s with lows Thu night
in the upper 40s to mid 50s.
Looking at the weekend, a quickly propagating trough well to the N
Thu and Thu night sends a deepening sfc low NE from the Canadian
Prairie out over Hudson Bay. This sends a weak sfc trough and a cold
front SE over the region Thu night into Fri. This quickly is
followed up by another deep trough and sfc low pair a bit closer to
home over N Ontario on Sat. The lack of instability and moisture as
well as the speed of which these systems move through leave much to
desire for precip chances. Given the model spread at this point,
confidence remains low in the fcst. The NBM for now remains dry
outside of Sat (15-20% chance for the E), but there is plenty of
time for this to change. What is more likely to occur during this
time is breezy winds.
Otherwise, temps by and large remain fairly steady the remainder of
the fcst with highs in the mid 60s to low 70s and lows in the 40s to
low 50s.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 722 AM EDT Tue Sep 23 2025
Continued low ceilings will prevail in this TAF period at all sites.
Morning LIFR will gradually improve through the day to VFR at KCMX,
but only to IFR or low MVFR at KIWD/KSAW. Tonight, fog and low
ceilings may return, potentially impacting all terminals.
&&
.MARINE...
Issued at 435 AM EDT Tue Sep 23 2025
Generally light NE to N breezes persist over the lake through mid
week, gusting ~15 kts over the E waters today into Wed. Winds are
expected to remain below 20 kt through at least Wed night, with
significant wave heights of 2 ft or less through the period. SE
winds increase up to 20 kts over the W half of the lake ahead of a
cold front Thu night into Fri. N to NE winds behind the front likely
will push into the 20-25 kt range across the lake into Fri. Another
cold front on Sat looks to bring similar wind speeds to the lake,
but more W to NW in direction. Otherwise, scattered showers over the
E continue this morning with isolated showers possible this
afternoon into tonight. This will support patchy dense fog this
morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Dense Fog Advisory until 9 AM EDT /8 AM CDT/ this morning for
     MIZ001>003-009-084.
Lake Superior...
  Dense Fog Advisory until 11 AM EDT /10 AM CDT/ this morning
     for LSZ162-240>244-263-264.
Dense Fog Advisory until 8 AM EDT this morning for LSZ245-
     248>251-265>267.
Lake Michigan...
None.
&&
$$
DISCUSSION...Jablonski
AVIATION...JTP
MARINE...Jablonski

NWS MQT Office Area Forecast Discussion