935
FXUS63 KDTX 280745
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
345 AM EDT Thu Aug 28 2025

.KEY MESSAGES...

- Showers spread across the area today with a chance of non-severe
thunderstorms, mainly this afternoon.

- Temperatures will remain below average for late August through the
end of the week.

- Dry weather with a warming trend through the holiday weekend.

&&

.DISCUSSION...

A band of showers is advancing south across northern Lower MI early
this morning, occurring within a corridor of deep layer moisture
convergence just ahead of a cold front currently draped from
northern Lake Huron across the Straits toward Green Bay. These
showers have upper support from an amplified shortwave trough/lobe
of vorticity dropping around an upper low as it tracks southward
just east of the ON/QC border. The shortwave tracks overhead from
late morning to early afternoon and allows for numerous showers to
spread across SE MI as the moisture axis pivots through.

Weak instability will develop as surface heating commences, peaking
mid-afternoon with SBCAPE up to 500-1000 J/kg achievable per the 00z
HREF. This brings a chance for scattered embedded thunderstorms
through the afternoon, especially south of the I-69 corridor. Bulk
wind shear will be relatively weak at 20 to 25 kt and severe weather
is not likely. The cold front arrives across the Tri Cities and
Thumb early this afternoon before continuing south and reaching the
Metro Detroit area by early evening. This will be marked by a
northerly wind shift with showers tapering off shortly afterward as
strong subsidence follows the shortwave. Gusty north winds of up to
25 to 30 mph are likely in the Thumb through the afternoon. Total
QPF has trended down with the latest guidance, with an average of
around 0.25" most likely for the area.

Following the front, 850mb temp drops from 8-9C to around 2C by
Friday morning. The cold advection and N to NNE wind direction over
Lake Huron will sustain weak instability and a slight chance for
lake effect showers across the Thumb into Friday. Otherwise, dry but
chilly conditions to finish the week as lows dip into the 40s (50s
Metro Detroit) and highs struggle to reach the upper 60s tomorrow.
The thermal trough moves off to the east by Saturday as the upper
low slowly eases into New England, so temperatures will begin to
rebound through the weekend.

Stable, dry conditions dominate Saturday into Monday as high
pressure sets up over the region in response to confluent flow aloft
and an anomalous ridge emerging over central Canada. The result will
be outstanding holiday weekend weather with the warming trend
sending highs back into the mid to upper 70s by Labor Day. Humidity
looks to increase slightly by Tuesday into Wednesday as return flow
arrives after the high begins to budge east. The best chances for
rain next week will arrive Wednesday into Thursday as a low ushers
the next strong cold front across the region.

&&

.MARINE...

The ongoing passage of a cold front has and will continue to pull a
line of showers with some embedded thunderstorms south across the
Great Lakes through the morning and early afternoon hours.
Convergence along the frontal boundary coupled with the rush of
cooler air behind the front does bring the chance for waterspout
generation through the day as wind direction backs from southwest to
north-northwest. Better mixing depths behind the front with the
cooler air will increase over lake instability, allowing sustained
winds around 20 knots with gust potential around 25 knots to then
persist through early Friday morning. Small Craft Advisories are in
effect across the outer Saginaw Bay and through Lake Huron
shoreline, lasting into Friday morning, for both wind and wave
concerns. High pressure quickly fills tomorrow through the day,
dampening some of the strong wind gusts and subsequent wave heights.

&&

.PREV DISCUSSION...
Issued at 1154 PM EDT Wed Aug 27 2025

AVIATION...

Shortwave ridging and the corresponding dry atmosphere in the lowest
15.0 kft agl will maintain VFR conditions through 09Z tonight. A
vigorous shortwave trough will dig aggressively southward into the
Central Great leading to strong height fall forcing. Prevailing
shower activity is expected to push into the northern terminals
after 10Z and the Detroit terminals after 14Z. Low level moisture
advection with cooling midlevels will effectively bring a chance for
some thunderstorms primarily during the middle of the day. An abrupt
wind shift to the north and northeast is timed out in the tafs.

For DTW/D21 Convection...Included a TEMPO for -TSRA between 18-21Z
Thursday.

THRESHOLD PROBABILITIES...

* High for ceilings below 5,000 feet Thursday morning.

* Moderate for thunderstorms Thursday afternoon.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 2 PM EDT this afternoon through Friday
     morning for MIZ049-055-063.

Lake Huron...Small Craft Advisory from 2 PM this afternoon to 10 AM EDT Friday
     for LHZ421-441>443.

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

$$

DISCUSSION...TF
MARINE.......AM
AVIATION.....CB


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at www.weather.gov/detroit.