textproduct: Detroit/Pontiac

KEY MESSAGES

- Weekend Shower Potential: Isolated showers possible today, with scattered showers developing Sunday afternoon primarily north of I- 69.

- Cool Sunday Night: Low temperatures fall into the 40s Sunday night as high pressure and cooler air settles over the area.

- Unsettled Midweek: Warmer and humid conditions return early next week, bringing multiple waves of of showers and thunderstorms Tuesday through Thursday.

DTW THRESHOLD PROBABILITIES

* Moderate for ceiling 5000 ft or less today and tonight.

* Low for a thunderstorm this afternoon and evening.

PREV DISCUSSION

Issued at 256 AM EDT Sat Sep 12 2026

DISCUSSION...

A well-defined shortwave tracking into western Kentucky/Tennessee will be opening up and absorbed by the northern stream trough tracking through the western Great Lakes. Just enough moisture advection and weak forcing will track into the southeastern half of the CWA today, along with enough destabilization (slightly negative LI's and SBcapes of 500-750 J/kg) to support the potential for isolated showers and possibly a stray thunderstorm. 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. This will provide a secondary focus for showers, but mostly over Lake Huron.

A deep 500 MB low over Hudson Bay on Sunday will direct a strong shortwave through the Straights. Timing is now in sync in with the peak heating of the day, and scattered showers seem likely north of I-69, closest to the mid level cold pool and moisture enhancement from Saginaw Bay. 850 MB temps dropping into the mid single numbers Sunday night will bring mins in the 40s as high pressure builds over the region. Low level flow looks to be mostly offshore Sunday night into Monday, but airmass is cold enough to potentially generate some lake effect showers which could graze the far eastern Huron and Sanilac counties before the tail of the upper level PV exits east and good subsidence kicks in.

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 and moist air will eject out of the southern Plains and fold over into Lower Michigan on Tuesday, as PW value reach around 2 inches. With showers and embedded thunderstorms likely developing during the day, max temperatures will likely be hindered and capped in the lower 80s. There is still some potential for the timing of FROPA to change slightly, however.

Medium range models continue to hang the front near the southern Michigan border before returning as a warm front Wednesday night and Thursday. Euro ensembles offer up a 40-50 percent chance for 24 hour qpf to reach or exceed half an inch.

MARINE...

High pressure will continue to bring benign marine conditions to the region through Saturday before unsettled weather comes back in to finish out the weekend. An active pattern returns late Saturday into Sunday as a low pressure lifts thought northern Ontario, dragging a cold front across the area in the morning. Overnight/early day arrival and detachment from the parent low greatly limit any shower and storm chances. Moderate trailing northwest flow develops over northern Lake Huron during the daytime on 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 into Tuesday. Preceding warm, humid airmass will fuel better scattered storm chances during this time.

DTX WATCHES/WARNINGS/ADVISORIES

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