textproduct: Detroit/Pontiac

KEY MESSAGES

- Low chance of a shower or thunderstorm today near the Ohio border; dry conditions prevail elsewhere today and Thursday.

- Showers and thunderstorms return Friday night, with the highest coverage and best chances on Saturday.

- Temperatures remain near normal through the period.

DTW THRESHOLD PROBABILITIES

* High for ceiling at or below 5000 feet first half of this morning, low be early afternoon.

PREV DISCUSSION

Issued at 324 AM EDT Wed Aug 19 2026

DISCUSSION...

A large and seasonably strong upper level low (544 DAM at 500 MB) is centered over James Bay early this morning and looks to exert its influence through the rest of the workweek. Respectable height falls this morning supported light showers with the slowly advancing cold front, although thunderstorms were hard pressed to materialize, as expected with the limited instability. The front looks to wash out close to the southern Michigan border as a weak PV filament breaks off from trailing shortwave over the Midwest and tracks through southern Lower Michigan late today. A secondary 850-750 MB Theta-E ridge is expected to track south of Eight Mile Road this afternoon, bringing enough instability near the southern Michigan border to offer up a low chance of shower or thunderstorm.

Otherwise, upper level confluent flow sets in, strong subsidence/mid level drying will allow for dry conditions tonight and Thursday as high pressure (1018 MB) translates east through the Central Great Lakes. A series of shortwaves is then on track to reinforce troughing over the Great Lakes region. The first one arrives Friday evening/night, with a second, stronger shortwave arriving Saturday that has the potential to cut off over the central/eastern Great Lakes Saturday night into Sunday. Numerous Showers and a few thunderstorms are likely on Saturday. A lower chance of showers continues into Sunday under cool cyclonic flow around as 850 MB temps drop below 10 C.

Temperatures look to remain near normal through the forecast period. High temperatures will generally hover within a few degrees of 80 degrees depending on the day, with overnight lows dropping into the 50s most nights.

MARINE...

Northwest flow takes hold this morning in the wake of a departing cold front. High pressure will fill in through the day which will promote light winds and dry weather, and will bring some more variable wind direction by the afternoon before veering winds east for portions of the southern Great Lakes. High pressure holds through Friday morning before departing east across the continental northeast. Active weather returns Friday afternoon and into the weekend as a cold front moves through the region. Rain showers and thunderstorms will become increasingly likely ahead of and along the cold front.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None.