054
FXUS63 KDTX 240334
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1134 PM EDT Sat Aug 23 2025

.KEY MESSAGES...

- Fall-like weather arrives to end the weekend and persists right
into Wednesday with highs in the upper 60s to mid 70s and lows
falling into the 40s early next week.

-Chance for brief light showers tomorrow and Monday, otherwise dry
for the mid week period.

&&

.AVIATION...

Persistent low level cold air advection tonight through Sun night
will follow the wake of this evenings cold frontal passage. The
passage of a mid level trough across Lower Mi Sun afternoon/evening
will deliver a reinforcing shot of cool air. Light winds and mainly
clear skies will last trough daybreak. Increased mixing through both
cold air advection and diurnal heating will then result in a modest
increase in the westerly winds by Sun afternoon, with gusts around
20 knots. Steep low level lapse rates and ample moisture, aided by
the Great Lakes, will support a broken VFR based strato cu field Sun
afternoon into the evening.

For DTW/D21 Convection...No thunderstorms are expected at this time.

THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet Sunday afternoon and evening.

&&

.PREV DISCUSSION...
Issued at 255 PM EDT Sat Aug 23 2025

DISCUSSION...

Large upper level low/trough over Ontario will be in no hurry to
exit east, leading to below normal temperatures to end the weekend
through early next week. Cold front tracking through southeast
Michigan late this afternoon will offer up the potential of isolated-
scattered thunderstorms as the strong cap around 750 MB seen on the
12z DTX sounding is eroded, leading to skinny capes aoa 1500+ J/kg.
0-6 KM bulk shear around 35 knots suggest an isolated cell could be
strong to potentially severe (less than 5%) if can get some enhanced
low level convergence with any marine layer interaction across the
Eastern Thumb region. Otherwise, unidirectional low level southwest
flow will make it difficult to sustain updrafts. The front looks to
be clearing all of southeast Michigan by 2z, with good drying and low
level cold advection kicking in. 850 MB temps to drop below 10 C by
Sunday morning, and under 7 C by Monday morning as a shortwave
currently over Central Canada provides a reinforcing shot of cold air
and amplifying the longwave trough over the eastern two thirds of
North America. With some moisture flux from the warm waters of the
Great Lakes, steepening low level lapse rates will likely be
sufficient to generate some light shower activity Sunday and Monday
as modest capes (100 J/kg) are embedded around the freezing level.
EQL levels look to mostly come up short of -20 C, with main threat of
thunder over the waters of Lake Huron.

The heart of the cold Canadian air will be in place on Tuesday, with
temps starting out in the 40s to start the days on both Tuesday and
Wednesday. A modest warmup then takes place Wednesday-Friday with
marginal height rises and low level southwest flow allowing 850 MB
temps to reach close to 10 C, allowing temps to at least get back to
normal values.

MARINE...

A low pressure system tracking east across James Bay will drag a
cold front through the central Great Lakes this evening, and perhaps
into the early overnight hours. Scattered shower and thunderstorm
development is expected ahead of the boundary, but some uncertainty
remains regarding the degree of coverage. Cannot rule out a couple
stronger storms capable of generating locally higher winds and/or
waves, thus some MWSs or SMWs may be needed. Cooler conditions
settle in behind the front for Sunday, and at least through the
first half of next week. This leads to better mixing potential
amidst stronger flow aloft, therefore gusts could approach Small
Craft Advisory conditions at times. Also monitoring low-end gust to
gale potential for the northern Huron basin, mainly for Monday
afternoon. Additional chances exist for shower/storm development
Sunday and Monday with isolated waterspouts possible, mainly over
portions of Lake Huron.

&&

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

$$

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


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.