textproduct: Detroit/Pontiac

KEY MESSAGES

- Showers and isolated thunderstorms this afternoon and again tonight. General thunder potential is slightly higher tonight.

- Thunderstorms potential again tomorrow afternoon, with a low-end chance for isolated damaging wind gusts. - Mostly dry Friday with low chance for showers south of the I-94 corridor.

- Warming temperatures this weekend, followed by much warmer and more humid conditions early through mid next week with periods of storms.

DISCUSSION

A low pressure system is moving across the western Great Lakes states this afternoon. Ahead of the low is a thetae ridge with gulf moisture supporting an area of precipitation moving into southeast Michigan at press time. Local environment remains limited in regards to instability and steeper lapse rates, which keeps thunderstorm potential low this afternoon. Rain and thunderstorm chances continue into tonight as the surface low moves through with associated frontal zone. Expectation is for coverage to be more focused along the warm frontal boundary as it lifts across southeast Michigan throughout the tonight period. The greater coverage potentially focused more south of M-59 early this evening then becoming more focused north of M-59 late tonight. Slightly greater instability is drawn into the area overnight tonight as well, which will continue to support the general thunderstorm potential. The better severe weather potential looks to stay to the west across southwest Lower Michigan and north/northwest Indiana. While PWATs are expected to climb above 1.00 inches this afternoon, overall forcing remains weak enough to keep any heavy rainfall potential pretty limited. This in turn should tame the hourly and 3 hourly QPF rates.

The weak low pressure system lingers over Michigan tomorrow along with moderate instability and CAPE depth available. Tall/skinny CAPE profiles with better shear available will support a low end potential for marginally severe winds with any of the stronger updrafts that are able to develop tomorrow afternoon. The sustained west-southwest flow will usher in a warmer airmass into the region tomorrow as well. Depending on how quickly clouds an clear across Lower Michigan, parts of Detroit Metro and points south may be able to make a run at 80 degrees. High pressure begins to gain greater influence locally towards the evening bringing an end to precipitation chances.

Surface high pressure across the north central Great Lakes and NNE flow trajectories will limit the northward leak of convection with a system moving across the Ohio River Valley on Friday, though low end PoPs (~30%) remain warranted south of the I-94 corridor. The rest of the area will remain dry with cooler flow decreasing afternoon highs for Friday by a few degrees down to the mid 70s. There will be a warming trend through the weekend as high amplitude ridge develops across the central CONUS into early next week. The easterly winds on Sunday will mitigate the warming to some degree with temperatures expected to climb solidly into the low-mid 80s for most of southeast Michigan for Sunday.

Long range models and ensembles offering at least moderate potential for extreme heat, especially during the mid-week period which would include several days with temperatures in the 90s and dewpoints into the 70s. Ensemble and AI solutions point towards mid 90s becoming achievable Tues/Wed translating to heat indices to 100 degrees or greater. Timing and duration of any convection riding around the ridge will need to be monitored during this time which would impact daily highs as is typical in these set ups.

MARINE

A weak low pressure system will slowly trek across central Lower Michigan this evening and tomorrow. This brings the potential for some rain showers, potentially even some thunderstorms, throughout this period. Winds are expected to be relatively calm throughout this period due to the overall weak pressure gradient of this low pressure system. If any thunderstorms were to develop during this time period they would be capable of locally higher wind gusts. After this system departs our area a high pressure system is expected to develop over our region throughout the weekend, bringing warmer and calmer weather along with it.

PREV DISCUSSION

Issued at 212 PM EDT Wed Jun 24 2026

AVIATION...

Thickening cloud cover precedes the first batch of rain showers on track to impact the airspace between roughly 20z-00z this evening. Plenty of dry air in place causes rain to evaporate as it moves east, thus the heaviest showers will be capable of MVFR cigs/vsby with otherwise VFR conditions through this evening. Little to no lightning observed upstream with even less instability over SE Michigan points toward just showers through dusk. Second round of storms firing over Wisconsin provides a better chance for thunder to survive this far east, but still too low confidence to include in the TAF. This activity pivots northeast this evening, arriving to the western edge of the airspace after 03z and may clip as far north as PTK. A bit more uncertainty as to when the back edge of these showers ends, but latest trends suggest early Thursday morning. Parent low then moves into northern Lower Michigan late tonight, boosting lapse rates and triggering additional scattered showers and possibly a few thunderstorms across the Saginaw Valley/Thumb after 06z tonight. Low chance for this to impact MBS/FNT, as favored initiation spot in the models is east of the terminals. Dry slot then quickly fills in Thursday morning, trapping low level moisture and causing MVFR to IFR cigs that will be at their lowest around daybreak. Clouds then begin to scatter Thursday as drier air fills in.

D21/DTW Convection...A few rounds of showers impact the DTW corridor beginning around 20z and ending early Thursday morning. Activity currently forming over Wisconsin and set to reach DTW after 00z tonight looks to be the best opportunity for thunder chances, although still low (about 30%).

DTW THRESHOLD PROBABILITIES...

* Moderate for ceiling at or below 5000 ft this afternoon, high tonight.

* Low for thunderstorms between roughly 00z and 06z tonight.

DTX WATCHES/WARNINGS/ADVISORIES

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