textproduct: Detroit/Pontiac

KEY MESSAGES

- Slightly cooler than average conditions today with rain chances persisting in the Thumb this morning.

- Warming trend for the middle of the week with the next chance of rain coming in the late Wednesday and Thursday period.

- Warmer and noticeably more humid conditions for the end of the week.

DTW THRESHOLD PROBABILITIES

* Moderate for ceiling 5000 feet or less today and this evening.

PREV DISCUSSION

Issued at 305 AM EDT Mon Aug 24 2026

DISCUSSION...

Deep upper level trough will maintain its influence over Southeast Michigan throughout the day. Combination of warm lake water temperatures with tight cyclonic flow will continue to bring lake effect or bay effect rain chances to the Thumb this morning. The outstanding question is when rain will eventually pull away from Huron County today. Forecast soundings support a fair amount of warming in the 3.0 to 6.0 kft agl layer after 15z as lower heights push eastward. The net result is that higher midlevel stability working into the top of the mixed layer should cause lake/bay effect to become more sparse by the afternoon today. Highs today are expected to be in the middle to upper 70s which is 2 to 4 degrees below normal.

Surface high pressure will build across the region tonight and Tuesday. Ideal lat e summer for Tuesday with daytime highs near 80 degrees and dewpoints in the 50s.

Warm front will lift across Lower Michigan Tuesday night and early Wednesday as broad troughing settles into the upper Midwest. Models have been very consistent in showing nothing more than a very weak upper level jet streak. Big picture perspective suggests that precipitation chances will rely heavily on when direct differential cyclonic vorticity arrives. This suggests sometime late in the Wednesday period particularly for areas south of I 69. This looks good as residual stability and dry air from strong subsidence the day before will be place Wednesday afternoon. The current forecast calls for dry or a slight chance in Detroit prior to 00z Thursday. Models then suggest a good amount of wave dampening which results in nothing more than a spoke of absolute vorticity early Thursday, unorganized embedded wave energy late Thursday and early Friday. Good confidence slightly more humid weather Thursday with dewpoints then dropping behind a cold front Friday.

Lower confidence exists regarding the forecast next weekend. There is some global deterministic differences on when the next Pacific jet packet will push into the Great Lakes region. GFS suggests as early as Saturday while the ECMWF waits until Sunday. Temperatures look to be in the 80s next weekend.

MARINE...

Post-frontal breezy northwest flow will persist as cooler air is ushered into the Great Lakes. Maintenance of wind gusts on the order of 20 to 30 knots is expected, along with some isolated gust potential to 35 knots across central Lake Huron. This higher end gust potential remains most favorable for the morning and early afternoon hours. Small Craft Advisories across the Saginaw Bay and into Port Huron have been extended through this evening.

Lingering rain showers and a very low chance for a waterspout also continues across Lake Huron, tapering off by the afternoon. High pressure will then begin building into the Great Lakes late this evening and will center over the region by tomorrow. Wind speeds start to diminish tonight as a result, leading to lighter winds tomorrow.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement through this evening for MIZ049.

Lake Huron...Small Craft Advisory until 8 PM EDT this evening for LHZ421-441>443.

Small Craft Advisory until 4 PM EDT this afternoon for LHZ422.

Lake St Clair...None.

Michigan waters of Lake Erie...None.