Troy, MI 48007 Weather

Key Messages

- Areas of fog tonight.

- Mild and dry through the week.

Discussion

The combination of clear skies under light east to southeasterly flow has resulted in the proliferation of dense fog through southern and central Michigan, and to a lesser extent across the Thumb. The favorable flow has brought about better moisture advection derived from Lake Erie inland, where continued advection along with gentle upsloping will see dense fog expand west and northwest through central MI. This will continue to promote fog across Monroe and Lenawee counties, where a dense fog advisory is in effect until 10 AM EDT. Portions of western Washtenaw, the Tri-Cities and Thumb will likely see periodic fog, possibly dense at times, through daybreak, with sunshine then works the lift and scour out fog through the remaining morning hours.

The familiar persistence forecast will again take hold today as high pressure sits over the Great Lakes, which will be reinforced through Friday as a longwave ridge expands through the Plains and Midwest/Great Lakes. Dry weather and above normal temperatures continue as a result through the weekend. Daytime highs will return into the upper 60s today and tomorrow and may make a push into the 70s by tomorrow afternoon. A very subtle decrease in highs (low to mid 60s) will be likely Friday with northeast flow coming off the lake, but as the aforementioned high pressure system starts to depart into the western Atlantic, low-level flow re-orients south to southwesterly, resulting in the gentle uptick in waa pushing highs back in the mid to upper 60s. Fog, dense at times, remains highly sensitive to wind direction as shallow lake moisture advection has been the main driver of recent events. Tomorrow morning fog is a possibility under clear skies, but the unfavorable flow lowers confidence relative to today. Friday morning will be much more conducive to advective fog given the light east to northeast flow off of Lake Huron and Saginaw Bay. Patchy to areas of dense fog will be possible through the Tri-Cities and Thumb with lowered confidence for the degree of expansion inland. Outside of morning fog concerns, dry and sunny weather continues through the weekend.

Marine

High pressure remains over the region through the end of the week resulting in benign marine conditions. The current high now centered over Quebec, will slowly shifts east through tonight with a dry cold front then passing southward early Thursday. This front will quickly be followed by another area of high pressure that will then hold through most of the weekend. Wind gusts will stay below 20 knots through the end of the week. Winds will be southerly today before flipping around to the north for Thursday behind the cold front early in the morning.

Prev Discussion

Issued at 1154 PM EDT Tue Oct 20 2026

AVIATION...

Conditions will become favorable for some degree of fog and/or very low stratus development late tonight. Forecast will continue to highlight a window for MVFR to IFR visibility restrictions with an entry level mention for very low stratus. There remains potential for one or more southeast Michigan terminals to witness a period of LIFR in fog/stratus, although confidence in occurrence remains too low to include attm. Any lingering fog/stratus will lift thru late morning, affording another period of clear skies with light wind for the remainder of the daylight period.

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

DTW THRESHOLD PROBABILITIES...

* Low for cigs/vsby to fall below 200ft and/or 1/2SM late tonight.