textproduct: Detroit/Pontiac

KEY MESSAGES

- Rain showers cross the area this afternoon. Scattered embedded thunderstorms possible mainly south of M-59.

- Summer-like temperatures Memorial Day through Wednesday with low rain chances.

DISCUSSION

Cool, cloudy start to the day following the slow departure of Friday's low. Active pattern set to continue today as Midwestern troughing is quick to flow, lifting a warm front into SE MI this morning. The fairly diffuse accompanying gradient keeps southwesterly winds on the lighter side however, limiting the magnitude of warm advection and moisture transport into the area. This is looking to result in both warmer temperatures (around 70) and higher dewpoints (lower 60s) only able to reach up around the M- 59 corridor before the arrival of upstream convection early this afternoon. Several hundred J/kg of SBCAPE are progged to be in place over these southern areas offering scattered thunderstorm chances within the broader shower activity. Given bulk wind shear values creeping into the lower 30kt range, can't completely rule out an isolated strong cell however the marginal instability and weak lapse rates (<6.5 C/km) will act to keep convection in check. For areas north of M-59, sufficient instability will be difficult to come by as dewpoints are favored to remain in the 50s with temperatures in the mid 60s. This has been picked up on in the latest CAM guidance with a trend towards decaying showers on the northern flank. Lingering rain ends around 00-01Z as the attendant weak cold front clears the region.

High pressure rapidly builds over southern lower MI tonight supporting clearing skies going into Memorial Day. High center drifts over Toledo to Lake Erie over the course of Monday ushering in light southwesterly return flow. In combination with sunnier skies, highs return back to the upper 70s to mid 80s- warmest in the Tri-Cities where the strongest WAA is focused. An isolated pop-up (thunder)shower is possible over the Saginaw Valley late afternoon- evening as several hundred J/kg of MLCAPE develop. Otherwise, dry weather holds across the area through Tuesday due to the influence of high pressure. Next chances for some scattered showers and isolated thunderstorms arrive daytime Wednesday as a backdoor cold front sweeps out of Lake Huron through SE MI. High pressure then builds back in to close out the work week.

MARINE

The low that passed over the region on Saturday will pull away to the east today but a mid level system will drive another front through the region today resulting in a chance of afternoon showers and thunderstorms for a few hours. Winds will become southerly by morning and southwesterly this afternoon behind the warm front. Gradient is weak thus winds are expected to hold at 10 knots or less. High pressure then starts building into the region tonight which will slowly pass eastward Monday and Tuesday keeping the weather quiet with light winds and waves. The high will reach the Mid-Atlantic coast by Wednesday with the Great Lakes then residing just north of a low over the Ohio Valley. A cold front will dropping southward through the region late Wednesday which could result in some showers.

HYDROLOGY

A cluster of showers and thunderstorms is forecast to track west to east across the area this afternoon. Most areas will receive under a quarter inch of rainfall, but there will be the potential for some areas to see up to 1 inch dependent on thunderstorms. This would be most likely to occur south of M-59. Overall dry conditions over the past 30 days suggests the potential for flooding is low, aside from typical isolated flood prone locations in urban areas.

PREV DISCUSSION

Issued at 1055 PM EDT Sat May 23 2026

AVIATION...

Expecting IFR to low MVFR ceilings to hold throughout the night. Given the expectation for stratus, decided to remove IFR mention of fog at daybreak. Wave of warm advection will lift through Southeast Michigan Sunday afternoon. A line of showers and embedded thunderstorms will be possible south of I 69 between 19-23z. Introduced a TEMPO for -TSRA at the Detroit sites.

D21/DTW Convection...A line of showers and thunderstorms will be possible between 19-23z Sunday. No severe weather is expected.

DTW THRESHOLD PROBABILITIES...

* High for ceilings at or below 5000ft into Sunday morning.

* Low for ceilings and visibilities to fall to 200ft or 1/2SM Tonight into Sunday Morning.

* Medium for thunderstorms Sunday afternoon.

DTX WATCHES/WARNINGS/ADVISORIES

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