textproduct: Detroit/Pontiac

KEY MESSAGES

- A chance of thunderstorms this afternoon and evening, with isolated storms capable of producing damaging winds, large hail and heavy rainfall. Greater potential exists between I-94 and the Ohio border.

- The potential exists for showers and thunderstorms to develop both Wednesday and Thursday.

- Drier conditions develop Friday and Friday night.

- Renewed chance of storms and heavy rainfall over the weekend.

DTW THRESHOLD PROBABILITIES

* Low to moderate for thunder this afternoon/evening.

* Low for ceiling 5000 feet or less this morning.

PREV DISCUSSION

Issued at 234 AM EDT Tue Aug 11 2026

DISCUSSION...

Large scale pattern will remain governed by lower amplitude mid level west-northwest featuring copious minor perturbations through mid week period. Low level frontal boundary effectively stalled near the IN/OH/MI state line marking the northern expanse of the deeper instability reservoir that resides just to the south. Pockets of convective development may continue to manifest this morning in the vicinity of the boundary, particularly as the low level jet folds into the existing frontal slope. This will offer a lower probability for mainly areas of south of I-94 to witness some early day activity. Otherwise, attention today squarely on behavior of the convective episode now organizing across South Dakota. Backed by a pronounced vort max and extremely receptive downstream environment, general expectation remains for a forward propagating MCS to accelerate into southern WI/northern IL by midday. From there, confidence in trajectory declines as a subset of the model solution space shows preference toward a path into the deeper instability parked to the south, while others do allow at least a portion of the system to arrive locally during the mid afternoon to early evening window. Greater potential with southward extent /particularly between the I-94 corridor and Ohio border/, where adequate deep layer shear and MLcape in excess of 2000 j/kg would support deeper convective organization with an associated damaging wind gust risk. Conditional localized heavy rainfall threat also certainly exists. High temperatures low to mid 80s again today.

Stagnant large scale pattern ensures similar underlying thermodynamic conditions exist both Wednesday and Thursday. Convective potential within this environment continues to carry strong reliance on finding tangible forced ascent in the form of additional shortwave energy to engage a profile featuring a standard degree of diurnal destabilization for mid August. Perusal of model guidance establishes little confidence in offering a more targeted opportunity. Absent of this, expectation for generally dry conditions to hold outside of perhaps a smaller scale response along any lake breeze activity. Outgoing forecast offers a more broad brushed chance mention highlighting the peak heating window each day.

High pressure briefly increases influence by Friday beneath confluence mid level northwest flow. This offers dry conditions to finish the week, as deep layer subsidence exists within a slight cooler and less humid conditions. Shortwave upper ridge will roll into the region Friday night and linger into at least the first half of the weekend. There is potential for a ridge running wave to lift across the region over the weekend, but again carries low predictable at this stage. Temperatures over the weekend generally remain seasonable.

MARINE...

A stalled front near the southern Michigan border will continue to be a focus for multiple rounds of thunderstorms over the next couple days. This will mostly affect Lake Erie and Lake St Clair but there is a chance of a few isolated showers farther north over southern Lake Huron. A strong complex of storms is forecast to track from the Midwest across southern Lake MI and toward the area this afternoon which could present a severe wind threat. Outside of any convection, high pressure to the north of the front will provide generally light and variable winds through mid week at 10 knots or less. Later in the week, a weakly organized area of low pressure becomes develops across the Northeast, followed by high pressure of 30.1 inches gradually dropping southeast across the central and eastern Great Lakes. This will favor an uptick in northwest winds Thursday and Friday.

HYDROLOGY...

While the axis of heaviest rainfall associated with repeated rounds of thunderstorms will remain to the south through tonight, there is potential for heavier rainfall to develop should more organized thunderstorms track into the area. The greater potential exists generally south of I-96 this afternoon and evening. Rainfall rates in excess of one inch per hour will be possible, which could lead to minor flooding in urban and poor drainage areas.

DTX WATCHES/WARNINGS/ADVISORIES

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