textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry and pleasant weather conditions will persist into Tuesday.

- Localized fog is possible this morning and again Monday morning.

- Rain chances increase during the latter half of next week with cooler temperatures expected.

DISCUSSION

A tranquil fall pattern continues for the next few days as high pressure remains in control over SE Michigan. The origin of the surface high however transitions away from Quebec and toward the emerging high pressure center over the Upper Midwest today. This will reinforce the northeasterly winds that we have seen for the past couple of days to maintain moisture flux off of Lake Huron. A slight increase in wind speed and upstream moisture content over Ontario suggests slightly more aggressive moisture flux than previous mornings. That said, synoptic scale moisture is still quite minimal with the 27.00z KDTX sounding sampling PWAT of 0.38" (10th percentile per SPC climatology). This has ultimately kept fog/stratus localized to the Thumb/Saginaw Valley. Similar fog/low stratus concerns will persist each morning until winds flip to the south Tuesday with the departure of the high.

Otherwise, seasonable temperatures hold in the low 70s over the next several days as the pattern remains at a standstill due to the stalled Nor'Easter. No signs of any meaningful thickness advection until Tuesday when flow flips southwest as the east coast system fills in and absorbs into the mean flow. By Tuesday night, mid level flow becomes zonal which opens the Great Lakes to a low amplitude shortwave by early Wednesday morning. Majority of guidance brings this Pacific wave and its accompanying upper level moisture across the state well ahead of low level Gulf moisture. This keeps rain chances low (<30%) for most of Wednesday in favor of just increasing cloud cover and possibly some virga. There remains disagreement in model guidance regarding timing of the gulf moisture surge, which will dictate when rain chances start to ramp up. This looks to be sometime Wednesday evening with rain chances then continuing through Thursday. Return flow will eventually be cut off as a cold front is dragged across northern CONUS by a northern stream low, which also ushers in an even cooler airmass to start off October as highs will only be in the mid-60s.

MARINE

High pressure now situated over the Great Lakes will hold through Tuesday. Some periodic wind gust potential around 20 knots will be possible across southern Lake Huron this afternoon and evening, but otherwise, wind gust potential to or below 15 knots is expected for most locations. Wind direction will mainly hold from the north to northeast with high pressure in place.

PREV DISCUSSION

Issued at 1151 PM EDT Sat Sep 26 2026

AVIATION...

Enhancement and deepening of subsidence along the periphery of the Northeast US closed low pressure will keep stable conditions over Southeast Michigan throughout the period. Center of surface high pressure will be in place over portions of Wisconsin and northern Lower Michigan. This will keep enough of a northeasterly gradient to allow for some surface based Lake Huron moisture to advect and pool over the northern forecast area. Surface condensation pressure deficits suggests a fog potential Sunday morning outside of the urban heat island. MOS guidance is now more supportive of low visibilities at FNT overnight. Maintained the lighter br in the tafs for the northern sites. Any fog looks to burn off late Sunday morning with a very dry sub 5.0 kft agl layer in place across the region.

D21/DTW Convection...Thunderstorms are not forecast through the forecast period.

DTW THRESHOLD PROBABILITIES...

* None

DTX WATCHES/WARNINGS/ADVISORIES

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