821
FXUS63 KDTX 061041
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
641 AM EDT Sat Sep 6 2025

.KEY MESSAGES...

- Cool this weekend with highs in the 60s and lows in the lower 40s.

- Isolated showers possible this afternoon and tonight.

- Warming temperatures next week.

&&

.AVIATION...

Cool midlevel temperatures between 4.0 and 8.0 kft agl in
combination with cyclonic vorticity advection has led to varying
coverage of VFR stratus over Lower Michigan this morning. Daytime
heating will again cause the development of boundary layer
cumulus/stratocumulus. This cloud is expected to hold through the
evening into tonight. Very low chance for a sprinkle or brief shower
exists between 21-03z today. Low confidence exists in coverage.

THRESHOLD PROBABILITIES...

* Low for cigs 5000 feet or less Saturday

&&

.PREV DISCUSSION...
Issued at 257 AM EDT Sat Sep 6 2025

DISCUSSION...

Latest water vapor imagery shows a shortwave tracking into the
Central Great Lakes this morning, with bulk of deformation
forcing/light showers expected to be confined to northern Lower
Michigan. Short lived subsidence/ridging for late morning hours
before another shortwave trough passes through during the late
afternoon hours. Isolated showers are possible with the steepening
low level lapse rates and sbcapes >50 J/kg. Even with the loss of
daytime heating, still chance for isolated shower activity tonight as
sharp shortwave trough/500 MB cold pool of -26 C drops southeast out
of southern Manitoba, and moves through the Central Great Lakes late
tonight (8- 12z Sunday). 850 MB temps of 2 to 4 C will be supportive
of some lake enhanced activity off Lake Michigan, which will have
the potential to peel off to the east and survive the trip,
especially around Saginaw Bay. Heights begin to slowly rise on
Sunday, but 850 MB temps of 5 to 6.5 C still translates to highs
stuck in the mid to upper 60s (close to 10 degrees below normal).

Surface high pressure (1027 MB) building over northwest Ohio Sunday
night will provide a good radiating night, with mins expected to dip
down into the upper 30s to lower 40s.

Warming next week with building heights (580-583 DAM at 500 MB) and
a strong warm advection pattern developing, as 850 MB temps push
into the lower teens on Tuesday and Wednesday. Highs around 80
degrees before a cold front pushes through Wednesday evening, but
the bulk of the cold air looks to be tracking into the Eastern Great
Lake and New England to end the work week.

MARINE...

As the strong low from Friday continues to pull further away from
the region, high pressure over the Plains has begun to build into
the southern Great Lakes and wind gusts have mostly dropped below 30
knots. Meanwhile, troughing aloft will keep a colder airmass over
the region through the weekend which will keep winds gusting into
the teens to lower 20 knots range out of the northwest and makes
waterspouts possible. Cooler, unsettled weather lingers into early
next week as the upper trough settles over the Great Lakes but
Tuesday and Wednesday may offer a break with warmer weather and
southerly flow ahead of the next trough.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 AM EDT this morning for LHZ421-422-
     441.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....CB
DISCUSSION...SF
MARINE.......DRK


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