textproduct: Detroit/Pontiac

KEY MESSAGES

- Warm through tomorrow. - Periods of scattered to numerous rain showers with embedded thunderstorms Friday afternoon into Friday night.

- Additional showers and storms are likely Saturday afternoon. Isolated to scattered storms may be strong to severe, capable of producing damaging wind gusts and large hail.

- A hot and stormy pattern is becoming increasingly likely during the middle of next week.

DISCUSSION

Warm and dry conditions persist through this evening as the prolonged ridge setup maintains control for one more night. The remaining influence of the ridge shrinks off to the southeast Friday morning with deep layer southwest flow ensuing the rest of the day. Remnant capping maintains dry conditions across the whole area initially, then a shortwave works into Mid MI by the early afternoon which helps erode the cap and ushers in a low-level theta-e ridge. A cluster of showers is likely to spread into Mid MI at the nose of the LLJ, then work across the Thumb. Mid-level lapse rates during this period are forecast to be weak to mitigate the threat for severe weather, but as higher boundary layer dew points advect in, enough instability will allow for scattered embedded thunderstorms. Farther south toward the Metro Detroit vicinity, the cap holds on through much of the day and allows temps to climb into the upper 80s and near 90 with relatively lower rain chances.

Higher instability builds in Friday evening and overnight ahead of a surface trough, providing fuel and forcing for additional showers and thunderstorms to spread across all of SE MI. Severe chances during this window remain low given weak lapse rates and weakening wind shear, but coverage of convection looks to be at its highest and can't totally rule out a stronger cell capable of marginal severe weather. A lull in shower/storm coverage is then likely Saturday morning as a subsidence bubble follows passage of the surface trough, allowing an inversion to strengthen and provide higher stability. As daytime heating erodes this cap, steeper low level lapse rates develop and allow SBCAPE to push 1000+ J/kg by early Saturday afternoon. A weakly forced cold front will sink southward across the area and provide the next potential trigger for convection, some of which may become strong to severe. Tall skinny CAPE and unidirectional shear point to water-loaded downbursts as the primary threat, but can't rule out large hail in any stronger cores. Cooler and more stable air works in Saturday evening to bring an end to rain chances.

Sharply rising mid-level geopotential heights provide highly stable conditions on Sunday, offering dry and seasonable summer weather that extends into Monday as well. Ensemble guidance is in strong agreement for an anomalous upper ridge to develop near Hudson Bay early next week. Our position just upstream of the ridge axis favors placement within an area of hot and unstable conditions. Daily temperatures will be subject to timing of convection, which carries high uncertainty at this stage. Magnitude of 850mb air mass at around 15 to 18C will be supportive of highs in the mid to upper 80s, and lower 90s look increasingly likely by late week.

MARINE

Warm southerly flow will keep wind speeds in check (mainly under 20 knots) due to the increased low level stability through tomorrow. A surface low tracking through the central Great Lakes tomorrow evening with bring numerous showers and a few thunderstorms to the region. Expected light, mostly westerly winds on Saturday. A weak cold front will sink southward late in the day, serving as the focal point for scattered, potentially marginally severe thunderstorms, with the highest probability over Lake St. Clair and Lake Erie. Very light northeast flow and dry conditions will follow for Saturday night and Sunday. Warm weather returns early next week, bringing a chance of showers and thunderstorms on Tuesday.

HYDROLOGY

Clusters of showers and thunderstorms are forecast to track west to east across Southeast MI Friday afternoon through Friday night. Another round of showers and storms is likely Saturday afternoon. Most areas will receive a quarter inch of rainfall or less, but there will be the potential for localized areas to see up to 1.50 inches. The extended period of dry conditions recently suggests the potential for flooding is low, but isolated flooding will be possible if any of the higher amounts affect the typical flood prone locations in urban areas.

PREV DISCUSSION

Issued at 116 PM EDT Thu Jun 4 2026

AVIATION...

Resident high pressure continues to command VFR conditions across the TAF sites for the rest of today. Southwest wind features occasional gusts in the upper teens through the diurnal cycle. Winds trend toward calm overnight beneath a persistent canopy of high cirrus. Gradient flow strengthens again Friday ahead of an advancing cold front that will lead to showers and some thunderstorms by the evening hours, currently outside the TAF period for sites other than DTW. Prior to 18Z Friday, ceilings will fill in and begin to lower into the mid-levels while staying VFR.

D21/DTW Convection...Showers with some embedded thunderstorm structures are possible after 21Z Friday.

DTW THRESHOLD PROBABILITIES...

* Medium for thunder Friday evening.

DTX WATCHES/WARNINGS/ADVISORIES

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