textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry conditions with near normal temperatures are expected through Saturday. The heat and humidity build back into the region Sunday and Monday.

- Thunderstorm chances increase late Saturday night and into early next week. Currently the best chance for strong to severe thunderstorms looks to arrive on Monday.

DISCUSSION

Large-scale troughing over the eastern US will continue to leave us under subsidence, with high pressure dominating the forecast through the first half of the weekend. This pattern will lead to continued dry conditions and comfortable, near-normal temperatures. Shortwave activity embedded within northwest flow aloft tracks south of the area Friday morning through Friday evening. While the forecast remains dry, areas along and south of M-59 will likely see an uptick in cloud cover.

The forecast looks to remain dry through much of Saturday, with the pattern turning more active for late Saturday night and into next week as a developing upper-level ridge becomes highly amplified across the central CONUS and strong northwest flow develops aloft. Being on the periphery of the upper-level ridge, we will see an uptick in warm air and moisture advection into the region. Both Sunday and Monday, 925-850 mb temperatures will support temperatures in the upper 80s, perhaps a few spots approaching 90 degrees. Dew point temperatures will also be on the increase as moisture moves in from the southwest, helping to push heat index values a few degrees higher than air temperatures.

The big question for the latter half of the weekend and into early next week are chances for strong to severe thunderstorms. As the heat and humidity build back into the region on the periphery of the upper-level ridge, we will need to keep an eye out for where thunderstorm activity initiates and tracks across the region. Medium range guidance continue to hint at numerous rounds of organized convective activity tracking from northwest to southeast across the western Great Lake region. At this time, southeast Michigan remains on the gradient of better instability building into the region and more than enough deep-layer shear for organized severe weather. Thus, we will need to keep a close eye the severe weather forecast for Sunday through Monday night. Looking at various AI/ML tools for Sunday, a few do highlight some of southeast Michigan for possible severe weather. Then for Monday, the SPC has southeast Michigan under a 15% Day 5 Outlook and a few AI/ML tools show the potential for even higher probabilities.

MARINE

Expansive high pressure in firm control, straddling the southern Great Lakes and northern Ohio Valley this afternoon. The strongest winds are across the northern third of Lake Huron, with a few gusts aoa 20 knots. Otherwise, winds are light and that will continue to be the case tomorrow, despite the center of the high moving over the Mid Atlantic. A surface trough slowly passing through during the weekend will bring a chance of showers and isolated thunderstorms, though winds are expected to remain light.

The next notable storm system arrives on Monday, as low pressure tracks across the northern Great Lakes. Strong thunderstorms are possible as the cold front works through the Central Great Lakes during the evening hours. Northerly winds behind this system late Monday night into Tuesday have the potential to reach 25 knots over southern Lake Huron.

PREV DISCUSSION

Issued at 115 PM EDT Thu Jul 23 2026

AVIATION...

VFR conditions will prevail through the TAF period as center of a surface high pressure drifts across the southern Great Lakes. This will bring stable conditions and light winds. Diurnal cumulus may get to SCT/BKN early this afternoon, but should mix out to FEW/SCT cumulus field late this afternoon and early evening. Tonight will carry a calm to light and variable wind and clear skies under 10kft. Expect a cirrus canopy to move over southern Lower MI late tonight and into Friday. FEW/SCT cumulus will develop again by late Friday morning.

D21/DTW Convection...No thunderstorms forecast.

DTW THRESHOLD PROBABILITIES...

* None.

DTX WATCHES/WARNINGS/ADVISORIES

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