109
FXUS63 KDTX 310950
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
550 AM EDT Sun Aug 31 2025

.KEY MESSAGES...

- Dry conditions will prevail through Tuesday.

- Showers and a chance of thunderstorms late Wednesday and Wednesday
  night will give way to much cooler temperatures late week.

&&

.AVIATION...

Prevailing atmospheric stability keeps winds and clouds in-check for
the terminals, through the next 24+ hours. Diurnal cumulus clouds
should struggle to expand beyond FEW-SCT coverage amidst drier and
warmer conditions, followed by another SKC night. Main forecast
concern is the renewed potential for pockets of nocturnal MVFR fog
which developed in isolated fashion last night. Fog mentions were
left out in this TAF cycle.

For DTW/D21 Convection...No thunderstorms expected during the
forecast period.

THRESHOLD PROBABILITIES...

* None

&&

.PREV DISCUSSION...
Issued at 310 AM EDT Sun Aug 31 2025

DISCUSSION...

A mid level anticyclone over the Manitoba/Ontario border will rotate
across the northern Great Lakes today, then become elongated as it
expands eastward into southern and northern New England tonight into
Monday. A weak area of mid level low pressure is forecast to develop
over the Mid Atlantic Monday, then lift northward toward upstate New
York and the eastern Great Lakes Tuesday. The 00Z model suite
indicates a ribbon of negative vorticity sliding across Lower Mi
Tues from the north as the weak upper low remains quite far east of
the forecast area. This pattern will support continued deep layer
subsidence across the region with broad sfc high pressure holding
across much of the Great Lakes today through Tuesday.

The overall forecast will be one of persistence for the next three
days. A slightly warmer thermal profile compared to yesterday will
be supportive of highs from the mid 70s to near 80 for the next
three days amidst ample sunshine. The dry continental airmass will
also sustain respectable nighttime cooling with lows dropping into
the upper 40s to mid 50s for the next several nights. The surface
ridge axis will remain positioned to the north of the forecast area,
sustaining light east winds for the next three days. Subtle low
level moisture flux off the lakes may therefore support a chance of
fog and/or low clouds tonight and Monday night. The higher
probabilities for fog are across the thumb and Port Huron regions.

The much advertised long wave pattern change will then begin mid
week as a potent mid level trough dives into the upper Midwest from
northern Canada. This wave will deepen into a closed mid level low
across the northern Great Lakes by the end of the week. Respectable
cold air advection for early September will follow in the wake of
the associated cold front late Wednesday, resulting in temperatures
10 to 15 degrees below seasonal norms Thurs and Friday. Ensemble
members generally indicate high rain chances along the lead edge of
the mid level height falls and deep layer moisture axis along/behind
the sfc cold front late Wed into Wed night.

MARINE...

Strong high pressure will remain over the region through Tuesday and
will result in light winds and dry conditions. A pattern shift mid
week will be characterized by strengthening low pressure across the
northern Great Lakes resulting in the passage of a strong cold front
late Wednesday. This will drive colder air across the lakes for the
end of the forecast period.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....KGK
DISCUSSION...SC
MARINE.......SC


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