733
FXUS63 KDTX 291639
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1239 PM EDT Sat Aug 29 2026

.KEY MESSAGES...

- Seasonable temperatures with dry weather through most of the day
today.

- Increasing chances for showers and storms tonight through
tomorrow. Shower and storm chances continue through the early week.

- Humidity builds for the early to mid week period.

&&

.AVIATION...

VFR conditions hold through the remainder of the daylight period, as
high based cloud thickens with time downstream of an area of
convection now lifting across Wisconsin. This moisture will lift
into lower Michigan this evening while gradually diminishing in
coverage and intensity. Expectation remains for simply a limited
probability for a few showers to survive, mainly at MBS, with little
consequence. Additional light shower development will remain
possible overnight, then with higher probability Sunday morning
again with higher probability at MBS/FNT. Warm front sets up over
the region Sunday, which may introduce the potential for a few
thunderstorms during the latter half of the day as instability
increases with daytime heating.

D21/DTW Convection...No convection is forecast through tonight.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 326 AM EDT Sat Aug 29 2026

DISCUSSION...

Rapid thunderstorm development is ongoing across the northern Plains
early this morning along the nose of a strengthening southerly LLJ.
This activity is expected to organize into an MCS and progress
through the Upper Midwest today before traversing into the Great
Lakes tonight into early tomorrow. Given little to no instability
across the Great Lakes, a weakening trend of this complex remains
favored, although latest hi-res guidance brings some increasing
confidence that portions of the MCS can reach Southeast Michigan.

This southerly low-level flow across the Plains will fold from Iowa
into Wisconsin through the morning hours and while the
aforementioned MCS is expected to outpace the nascent moisture
source, the nocturnal reinforcement of the LLJ could support
redevelopment or reinvigoration of showers and embedded
thunderstorms along the backside of the MCS despite limited
instability. This can support rain and thunderstorm chances into the
early afternoon across SE MI. Additionally this corridor of enhanced
theta-a will strengthen isentropic ascent along or north of the I-69
corridor, providing continued support for showers and thunderstorms
into the latter half of the day. Development along this convergent
boundary in the afternoon/evening would likely be a little more
localized. Overall there remains uncertainty regarding how these
individual potential rounds of precipitation will evolve and
overlap, but confidence has increased in a considerably more
unsettled Sunday.

Given the above, confidence is increasing that NBM temperatures are
likely overdone on Sunday. An active convective pattern and
persistent cloud cover will limit meaningful insolation. If the more
active setup plays out as projected, highs will be capped in the
70s, with low 80s possible only where coverage is reduced for a
longer period of time.

A very moist and active pattern will persist in the early and
midweek period. Ensemble guidance highlights strong west to east
integrated water vapor transport across the region into Wednesday.
PW values of 1.75 to 2.00" and warm-cloud depths approaching 13kft
will support efficient rainfall production. Mid-level disturbances
within quasi-zonal flow under this setup will bring multiple
opportunities for showers and thunderstorms. Repeated convection
along the same areas will bring a localized flooding risk. In the
same regard for Sunday temperatures, early week highs will be
conditional on cloud coverage and shower chances. Temperatures will
likely need to be tempered down if new guidance highlights SE MI as
a susceptible corridor for repeated precipitation.

MARINE...

Influence of high pressure wanes this morning as it shifts to the
Northeast with the central Great Lakes holding on its westernmost
fringe. This allows for modest southwest winds to develop during the
day with gusts holding aob 20kts, save for central Lake Huron where
favorable fetch could allow for up to 25kts. Active pattern returns
by Sunday as developing low pressure over the northern Plains lifts
a warm front through the area ushering in a more humid airmass
leading numerous shower/storm chances Sunday into Monday.

&&

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

$$

AVIATION.....MR
DISCUSSION...AM
MARINE.......KDK

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at www.weather.gov/detroit.