textproduct: Detroit/Pontiac

KEY MESSAGES

- Warming trend through the middle of the week with increased humidity.

- Next chance for showers and thunderstorms arrive late Wednesday. An isolated strong storm possible Wednesday evening.

- Lingering chances for isolated showers/storms Thursday afternoon.

DTW THRESHOLD PROBABILITIES

* None.

PREV DISCUSSION

Issued at 331 AM EDT Tue Aug 25 2026

DISCUSSION...

Progressive shortwave ridging aloft will push across the Great Lakes today supporting surface high pressure. Differential geopotential height rises and increased thickness will support a notable uptick in daytime temperatures. Highs today are expected to be near 80 degrees which is right at lake August seasonal averages.

Next Pacific upper level jet packet and reasonably well organized upper level low pressure circulation will dig into Lower Michigan Wednesday and Wednesday night. Residual stability and subsaturated airmass between 3.5 and 9.0 kft agl will lead to quiet weather conditions for early and midday Wednesday. Will likely be looking at two thetae warm front structures the first bringing iso-sct showers and virga 16-20z, the second associated with cyclonic flow and greater convergence along a prefrontal trough at 23z Wed to 05z Thu. Wind progs suggest 850mb winds/LLJ increasing +30 knots immediately in advance of the prefrontal trough contributing to 0-6km bulk shear magnitudes of 30-35 knots. Forecast soundings continue to show statically stable conditions throughout the lowest 4.5 kft agl which casts doubt on whether or not thunderstorm activity will be elevated. Regardless, marginal instability at around or less than 1000 J/kg limits much in the way of widespread severe weather. Latest Swody2 has the majority of Southeast Michigan in a Marginal risk for severe weather primarily for the late afternoon and early evening hours. A portion of western Lenawee County is designated in a Slight risk for severe weather as there is some potential for supercells to the southwest of the area.

Models suggest a good amount of wave dampening which results in nothing more than a spoke of absolute vorticity Thursday. Deep cyclonic flow with steeper lapse rates aloft brings an isolated chance of showers Thursday afternoon. Good confidence in additional humidity on Thursday with dewpoints then dropping behind a cold front Friday.

Confidence appears to be increasing that any Pacific shortwave energy will wait until very late in the weekend. GFS has come more in line with the ECMWF in keeping surface high pressure in place Saturday.

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. Another very nice late summer weekend looks likely.

MARINE...

High pressure will settle over the Great Lakes today and will support light winds and dry weather. Southwest flow will become better established by tomorrow ahead of an upper-level disturbance and cold front, which will increase wind speeds across Lake Huron given the more favorable fetch. Wind gusts around 20 to 25 knots will be increasingly likely with the southwest flow as rain showers and some thunderstorm begin to build in. Shower and thunderstorm chances will persist into Thursday morning with the passage of the front. Post frontal northwest flow will take hold through the day on Thursday with low-end chances for rain showers. High pressure then builds back in Friday to end the week.

DTX WATCHES/WARNINGS/ADVISORIES

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