textproduct: Detroit/Pontiac

KEY MESSAGES

- Showers with a rumble of thunder continue into early morning, mainly south of the Tri Cities and northern Thumb, transitioning to light rain before ending toward noon.

- Dry weather moves in this afternoon and continues tonight and Tuesday.

- Slightly cooler than normal temperatures continue through mid to late week.

- The next chance of rain arrives Wednesday and Wednesday night.

DTW THRESHOLD PROBABILITIES

* High for ceiling at or below 5000 ft most of today.

PREV DISCUSSION

Issued at 353 AM EDT Mon Jun 22 2026

DISCUSSION...

Clusters/bands of showers are in progress over southern Lower Mi primarily associated with the strong mid level circulation that is the parent to Ohio valley surface low pressure. The system is still supporting a wide range of convection from severe thunderstorms along and ahead of the surface fronts, to elevated but still cellular showers north of the surface low, to the clusters/bands across much of southern Lower Mi. Lightning has been absent north of the IN/OH border since midnight, however rainfall rates have still been quite productive as the leading stratiform component last evening quickly transitioned to clusters/bands as 700 mb isentropic lift and frontogenesis activated ahead of the 500 mb circulation. The most intense concentration of clusters and banding produced event rainfall totals in the 0.75 to 1.25 inch range from northern IN into SW Lower Mi based on surface observations and radar estimates since 00Z last evening up to press time.

There is still an additional round of showers and a rumble of thunder yet to go as radar coverage steadily fills in over central IN/OH. This is where the low level jet activates new convection within the 850-700 mb theta-e gradient before veering eastward with the surface low center. HREF and REFS 3 hr PMM QPF capture this reasonably well and show it grazing the SE MI area south of I-94 from now through sunrise. After that, precipitation rate diminishes while coverage is maintained by mid/upper level deformation from about the mid Thumb shoreline to Lansing during early morning. There is good agreement in the 00Z models that all rain ends in SE Mi around Noon.

Satellite imagery upstream across the northern Great Lakes then supports a decreasing cloud trend over SE Mi this afternoon, although it may take until late afternoon to clear Detroit. Decreasing clouds is mainly associated with larger scale subsidence trailing the morning low pressure system as low level northerly flow is just slightly cooler and less humid. The inbound high pressure air mass gains greater presence late tonight and Tuesday as the mid/upper level short wave ridge builds over the Midwest while keeping the surface ridge to our west. This maintains moderate northerly wind in the low levels that is still mild enough for a fair weather cumulus field in the afternoon. Guidance highs in the mid to upper 70s further supports this air mass just maintaining the already slightly below normal temperature pattern of recent days.

High pressure holds Tuesday night, but just barely, as the long wave mid/upper air pattern remains less amplified and progressive. This has the current Canadian Rockies system reaching the Great Lakes without much fanfare Wednesday and Wednesday night. Model consensus tracks the surface low through the northern Great Lakes which sets up a standard warm front/cold front progression across SE Mi for our next chance of showers and thunderstorms. This is another system that brings little change of air mass as guidance temperatures hold in the mid to upper 70s post front on Thursday. This could change as extended range models indicate a larger pattern shift occuring next weekend resulting in a large closed low over the Rockies and a downstream ridge over the Midwest. Guidance high temperatures in the mid 80s are offered in SE Mi by Sunday.

MARINE...

A compact low pressure system will travel east across the Ohio Valley through the morning. This will sustain east to southeast flow across Lake Erie, and wind gust potential around 25 knots along with elevated wave heights. A Small Craft Advisory remains in place. Some isolated wind gusts 20 to 25 knots will be possible across Lake St. Clair this morning, with lower magnitude wind speeds across Lake Huron and the Saginaw Bay. Widespread rain continues across the southern Great Lakes, tapering off in the late morning to early afternoon. Wind direction backs north to northwest in the wake of the low through the early week period as high pressure builds in. Lighter winds are expected tomorrow and Wednesday.

HYDROLOGY...

Widespread showers are in progress over SE Mi generally south of the Tri Cities and northern Thumb. There is a chance of locally heavy rainfall in this pattern through early morning, especially toward the Ohio border. Event total amounts of 0.5 to 1.0 inch are likely along and south of I-69, with a chance of localized totals around 1.5 inches mainly south of Detroit to the Ohio border before intensity diminishes considerably around sunrise. These rainfall totals and time ranges suggest the potential for flooding will be limited to ponding of water on roadways and other prone areas.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement until 5 PM EDT this afternoon for MIZ083.

Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...Small Craft Advisory until 5 PM EDT this afternoon for LEZ444.