textproduct: Detroit/Pontiac

KEY MESSAGES

- A slight chance for a shower or thunderstorm on Saturday, otherwise a quiet weekend, accompanied by slightly above-normal temperatures.

- Showers expected to return by the middle of next week.

DTW THRESHOLD PROBABILITIES

* Moderate for ceiling 5000 ft or less late tonight.

PREV DISCUSSION

Issued at 251 AM EDT Fri Sep 11 2026

DISCUSSION...

Latest water vapor shows dry mid levels over southeast Michigan, which is also confirmed by the 00z DTX RAOB, which indicated a 700 MB dew pt depression of 20 C with a PW value of 0.59 inches. This dry air mass will hold today, although patchy ground fog looks to be around to start the day. Return flow around the departing high pressure will increase this evening and tonight. A shortwave over Missouri will shear off to the northeast today and mainly track through the eastern Great Lakes Saturday morning. Still, sufficient moisture tracking into eastern half of the CWA, along with enough destabilization (slightly negative LI's and MLcape of 750+ J/kg), will support the potential for isolated showers and thunderstorms (see 00z HRRR/RRFS). A secondary moisture axis out ahead of a cold front will also track in from the western Great Lakes late in the day, passing through during the evening or washing out altogether. The bulk of the shower activity is expected to reside over Lake Huron however.

With cooler cyclonic flow on Sunday, its still not out of the question for isolated light showers before a mid level dry slot becomes fully established over southern Michigan. 850 MB temps dropping into the mid single numbers Sunday night will bring potential for mins in the 40s as high pressure builds over the region. The wild card is whether low clouds develop with the light onshore flow off the warm waters of Lake Huron.

A strong storm system will track through the northern Plains on Monday and into northwest Ontario Monday night. The active warm front is expected to reside over western Great Lakes. Warm air will eject out of the southern Plains, with the 00z Euro indicating 850 MB temps warming to 20 C; setting up Tuesday as sneaky warm day ahead of cold front. Timing of FROPA and extent of cloud cover and showers is uncertain, but high temperatures in the 80s seems reasonable. Mid level frontogenesis hanging around Tuesday night into Wednesday will offer up a continued good chance of rain.

MARINE...

High pressure in place through tonight maintaining benign marine conditions. Active pattern returns late Saturday-Sunday as low pressure lifting through northern Ontario drags a cold front across the area in the morning. Overnight/early day arrival and detachment from the parent low greatly limit any shower/storm chances. Moderate trailing northwest flow develops over northern Lake Huron daytime Sunday with peak gusts between 25-30kts. This front looks to stall somewhere near southern Lake Huron offering an isolated shower chance into Monday. A more dynamic system then lifts out of the Plains and over the northern Great Lakes Monday night-Tuesday. Preceding warm, humid airmass will fuel better scattered storm chances.

DTX WATCHES/WARNINGS/ADVISORIES

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