textproduct: Detroit/Pontiac

KEY MESSAGES

- There is a chance of showers and thunderstorms today with an isolated risk for strong to severe storms.

- Additional chance for showers and embedded thunderstorms on Sunday as a low pressure system drifts south of the state. There is an even lower chance for isolated strong to severe storms.

- Heat and humidity remain to start the weekend but at more manageable levels with highs in the mid 80s and heat indices in the low to mid 90s today.

DTW THRESHOLD PROBABILITIES

* Low for thunderstorms this afternoon, medium late tonight.

* Low for ceilings at or below 5kft today.

PREV DISCUSSION

Issued at 337 AM EDT Sat Jul 4 2026

DISCUSSION...

Hot and humid conditions remain across the region on this Independence Day as zonal flow pattern has positioned itself across the Great Lakes locking in this airmass another day. There are slight changes over the days past as the most unstable air has been shunted south by the southward advancing outflow boundary resultant of the multiple storm complexes over the last couple days. This should provide focus once again today for stronger surface based convection. A second boundary is setting up across Mid MI as high pressure builds over Ontario, focusing the active mid level wave train across that region. Temps will once again rise into the 80s, to near 90 close to the Ohio border with dewpoints still around 70. PWATS have come down a bit but remain around 1.5 inches which is plenty for storms to work with. Primary forcing for convection will be the passing mid level waves with the first exiting the area early this morning. Could see a several hour dry period before the next wave drift down across the Mid MI frontal boundary looking to fire the next round of storms which would drift east and south through the afternoon. CAPE is a bit lower around 1500-2000 J/kg with modest shear around 20 knots and decent low level lapse rates but mid level lapse rates are a bit underwhelming leading to tall skinny CAPE. All in all, expecting another round of convection this afternoon into evening with isolated strong to severe storms possible. Damaging winds will be the primary threat with hail and isolated flooding risks still possible. SPC has the region in General Thunder with Marginal Risk along the state line.

A stronger mid level trough drifting across the central Plains will deepen over the Mid MS Valley Sunday with an associated surface low in that general area. Isentropic ascent ahead of the low will increase the theta e over SE MI with the deformation axis passing over through the afternoon. This should lead to a longer duration rain over far southern MI with showers and embedded thunderstorms, with a sharp cutoff to drier conditions across the northern counties. The passage of the cold front late Saturday and the low to the southwest will flip winds around to the northeast providing additional level of relief from the warm humid airmass, with highs around 80 and dewpoints falling to around 60.

The low will still be south of the area on Monday providing some chance for rain but continues dry air advection from the northeast will lower probabilities. The mid level trough pulling away opens the door for ridging to build back over the region through the start of the week. Slow warming trend through mid week with persistent ridging opens the door for high temps to inch back up toward 90 for Wednesday and Thursday.

MARINE...

Ambient winds will remain light outside of any isolated or scattered showers or thunderstorms that can bring some localized stronger gusts this morning. A weak cold front does sweep through today which will pivot wind direction from the northeast, with the frontal boundary stalling around southern Michigan. Additional shower and thunderstorm chances will continue through the weekend given the warm and humid airmass. Some stronger storm development will again be possible both today and tomorrow, favored across the southern Great Lakes. Any stronger thunderstorm will be capable of producing wind gusts aoa 40 knots.

DTX WATCHES/WARNINGS/ADVISORIES

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