549
FXUS63 KDTX 241645
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1245 PM EDT Sun Aug 24 2025

.KEY MESSAGES...

- Cooler weather arrives today and persists through much of the week.

- Chance for brief/scattered light showers today and tomorrow.

- Mostly dry mid to late week with the exception of Thursday.

&&

.AVIATION...

Increasing mixing depths will allow westerly winds to gust up to 20
knots this afternoon. Chaotic VFR cloud bases in the 4-10 kft range
around, with isolated-scattered embedded showers briefly allowing
cigs aob 4000 feet. There is a very low chance of embedded thunder,
mainly northern taf sites.

Despite the loss of daytime heating, some clouds will likely persist
this evening and tonight as low level cold advection continues. With
northwest low level winds, the northern tafs stand the best chance
for cigs as a Lake Superior-Lake Michigan moisture connection
develops, and have decided to include a low VFR ceiling toward/by
sunrise. Another round of diurnal enhanced isolated-scattered shower
activity likely tomorrow.

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

THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet, as skies will likely be variable
  through much of the taf period.

&&

.PREV DISCUSSION...
Issued at 347 AM EDT Sun Aug 24 2025

DISCUSSION...

Deeper troughing extending from a low over James Bay will begin to
take hold of the Great Lakes today. Cooler air within the northwest
flow is already settling into the region in the wake of last night`s
cold front. Temperatures to start the day will be in the 50s for
most of the area aided by the clear skies providing favorable
cooling conditions. A noticeable drop in daytime high temperatures
will be observed today with afternoon highs around the mid 70s along
with comfortable dewpoints in the 50s. A shortwave originating from
central Canada will wrap up into the base of the broader trough over
the Central Great Lakes this afternoon providing a boost in larger
scale lift over the area during peak heating. This combined with
steepening low level lapse rates, weak elevated instability, and the
added moisture flux off the of lake should support scattered shower
development during this afternoon into the early evening. Best
chance for thunder will favored north of I-69 and over Lake Huron.

The aforementioned wave will also send a reinforcing shot of cold
air that will drop 850 mb temperatures down to around 5C by by
tomorrow morning. The cooling trend continues with another
noticeable drop in daytime highs down into the upper 60s to low 70s.
Similar to today, another wave will be rotating through the cyclonic
flow and provide a boost in lift that will be favorably timed with
peak heating. Presence of weak elevated instability and maintenance
of lake moisture flux in northwest flow will again bring
precipitation chances (around 30%). Thunderstorm potential looks
pretty limited.

Cool Canadian trough holds over the region into mid-week making for
a cold start to Tuesday and Wednesday morning with morning lows
dipping into the 40s for most of the area outside of the urban heat
island of Detroit. With minimal air mass modification on Tuesday,
highs will be similar to Monday with highs in the upper 60s to low
70s. Surface high pressure will begin to migrate from the northern
plains and through the the Ohio Valley mid to late week with slight
moderation of the airmass bringing daytime highs back up into the
low to mid 70s Wednesday to Friday. Frontal boundary dropping south
will bring the next chance of precipitation on Thursday. Otherwise
bulk of the mid to late week should be on the dry side.

MARINE...

Cooler conditions settle in behind a cold front today and last at
least through the first half of the week. This leads to better
mixing potential amidst steeper lapse rates and stronger flow aloft.
Gusts could approach Small Craft Advisory conditions at times,
particularly for Saginaw Bay and The Thumb. Also monitoring potential
for gusts to gales across the northern Huron basin, mainly for
Monday afternoon. Additional chances exist for shower/storm
development today and tomorrow 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.....SF
DISCUSSION...AA
MARINE.......KGK


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