textproduct: Detroit/Pontiac

KEY MESSAGES

- Showers and scattered thunderstorms spread across southeast Michigan Friday night into Saturday, bringing widespread rainfall. Severe weather is not expected.

- Cooler and breezy conditions arrive Sunday with lingering shower chances and gusts reaching 25 to 30 mph.

DTW THRESHOLD PROBABILITIES

* None.

PREV DISCUSSION

Issued at 255 AM EDT Thu Aug 20 2026

DISCUSSION...

An amplified upper level pattern is setting up over the CONUS as we head into the Weekend, with a ridge over the Rockies and trough east of the Mississippi River Valley.

A couple of showers survived into southwest Lenawee County last evening. A continued southward drift of the moisture gradient will occur today, but an isolated shower south of I-94 corridor today still can not be ruled out, as low level easterly flow off the warm waters of Lake Erie may provide just the moisture/convergence boost needed. Still, LI's should hold aoa zero, thus thunderstorms are not expected.

The next shortwave and associated surface low moves into the Western Great Lakes tonight, with a second shortwave and round of height falls quickly catching up and merging over the central Great Lakes Friday night into Saturday. Good low level convergence along the cold front will support blossoming showers and scattered thunderstorms on Saturday. SBCAPE under 1500 J/kg and weak mid level lapse rates should keep activity sub-severe, as 0-6 KM bulk shear is also on the lower side (under 30 knots). Euro ensembles indicate a 90+ percent for a tenth of an inch or greater of qpf, with a 20 to 40 percent chance of a half an inch or greater over the north half of the CWA.

Cool cyclonic flow for the second half of the weekend will keep a chance of showers going, especially if the 00z Canadian verifies with the timing and position of the next strong spoke of energy rotating through. It look to be a bit breezy as well, with gusts in the 25-30 mph expected with cold advection and deeper mixing.

Closed 500 MB low just north of Georgian Bay Sunday evening will maintain cooler weather to start next week. A short lived warming trend then kicks in Tuesday into Wednesday, but an even deeper trough and cold shot is forecasted for Thursday and Friday, as the Euro indicates 850 MB temps reaching 6-7 C.

MARINE...

High pressure over northern Lake Huron will provide light northeast winds today, turning southeast tonight ahead of an approaching cold front. This front over the western Great Lakes will be slow to advance east. South-southeast winds on Friday will have the potential to reach 20 to 25 knots over northern Lake Huron. Showers and scattered thunderstorms will then move through Friday night and Saturday as the cold front finally tracks through the Central Great Lakes. Strong northwest winds will follow for Saturday night and especially Sunday, with frequent gusts of 25 to 30 knots expected over Lake Huron as colder air filters in. Gradually decreasing winds Sunday night into Monday as a large area of high pressure returns Monday night.

DTX WATCHES/WARNINGS/ADVISORIES

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