textproduct: Detroit/Pontiac

KEY MESSAGES

- Breezy and cooler conditions arrive today with scattered showers into tonight.

- Dry weather Monday into Tuesday with a warming trend. The next chance of showers and storms is possible late Wednesday and Thursday.

DISCUSSION

Stacked low pressure system spinning just to our east over southern Ontario will lift northeast into Quebec overnight. We're dealing with cold advection on the backside of the low today with a strong mid level wave passing over this afternoon before the low finally departs. Atmosphere utilizing the low level moisture one last time this afternoon with a round of scattered showers before ridging pushes in and dries out the mid levels ending precip chances later this evening. SPC Mesoanalysis shows around 250 J/kg of CAPE mainly in the Thumb with a band of low level convergence stretching from MBS to PHN. This has been enough to generate some showers in the area. Weak mid level lapse rates and little instability should help minimize much of any lightning. Cool night in store as dewpoints have already fallen to around 50 and even the mid 40s across northern MI. Once the diurnal clouds mix out we should clear out for the most part. Questionable area will be the eastern Thumb where the cloud shield from the upper low continues to reach back toward the area. Clouds would help hold those temps up a few degrees if the clouds never release.

Surface high builds in tonight for Monday and Tuesday while upper level heights also inch upwards. We'll keep the northwesterly flow Monday helping to hold highs temps on the cool side again in the mid 70s, but the ridge axis passes on Tuesday allowing for some warmer return flow to get us back up toward 80.

Next trough affect the region mid week with a warm front pushing north of the area Tuesday evening tied to a low passing through the northern Great Lakes. Upper level waves start ejecting out of the trough over the region Wednesday leading to increasing chances of rainfall before the main trough axis and cold front sweep through early Thursday.

MARINE

Post-frontal breezy northwest flow will persist through tomorrow as cooler air is ushered into the Great Lakes. Wind gusts ranging between 20 to 30 knots are expected during this window, along with some isolated gust potential to 35 knots through this evening, focused mainly across north-central and central Lake Huron. Given the lower confidence for any longer duration gale potential, will continue to preclude any issuance of gale products. Increasing coverage of rain showers will be likely tonight into tomorrow morning across Lake Huron, including a very low chance for waterspouts along any convergence axis. High pressure will then begin building into the Great Lakes Monday evening, centering over the region by Tuesday. This will diminish wind speeds tomorrow night, leading to light winds by Tuesday.

PREV DISCUSSION

Issued at 133 PM EDT Sun Aug 23 2026

AVIATION...

Low pressure continues to occlude over the Ontario/Quebec border, with cyclonic gradient flow on the backside of the low peaking around 15 knots with gusts up to 25 knots. Wrap-around moisture pairs with lake moisture flux to support low VFR ceilings through most of the TAF period as well. Isolated shower coverage peaks through the diurnal cycle followed by a window of decreasing cloud coverage to SCT-FEW this evening. A second pool of moisture over central Ontario releases south tonight into Monday, bringing another opportunity for low VFR cigs. The airspace will be on the outer edge of the moisture gradient meaning fluctuations in coverage will be possible throughout the day. Otherwise, breezy west-northwest winds and dry conditions expected Monday.

D21/DTW Convection... very low potential for an isolated thunderstorm this afternoon and evening.

DTW THRESHOLD PROBABILITIES...

* Moderate to high for ceiling 5000 feet or less today and tonight.

* Very low for an isolated thunderstorm this afternoon and evening.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement through Monday afternoon for MIZ049.

Lake Huron...Small Craft Advisory until 4 PM EDT Monday for LHZ421-441>443.

Small Craft Advisory until 4 AM EDT Monday for LHZ422.

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