textproduct: Detroit/Pontiac

KEY MESSAGES

- A statewide Air Quality Alert today as additional wildfire smoke filters across Michigan.

- The next round of showers and thunderstorms arrives Monday night into Tuesday that poses a Marginal Risk for severe weather.

DTW THRESHOLD PROBABILITIES

* Low in ceilings aob 5000 feet today and tonight.

PREV DISCUSSION

Issued at 337 AM EDT Sun Jul 19 2026

DISCUSSION...

Post frontal northerly winds will usher in a cooler airmass today bringing daytime highs down to a few degrees below seasonal norms. High temperatures this afternoon will range from the mid 70s to low 80s. The northerly winds will also allow wildfire smoke from Canada to linger over the state with another band of near-surface smoke funneling down through southeast Michigan early today. Thus, the air quality alert is in place again today and for all of southeast Michigan. Smoke models do show lesser concentrations over much of southeast Michigan by this evening into tonight, but hanging out over the western portion of the state.

High pressure moves across the state today and drifts off the Mid- Atlantic coast tomorrow. This will bring stable conditions and a forecast free of precipitation through tomorrow afternoon. Passing of the high pressure will lead to southwest return flow, which may draw nearby wildfire smoke back into the area Monday. It will also bring warmer air back into the region along with slightly better moisture. This will result in temperatures tomorrow afternoon right around normal values. Deeper moisture will arrive tomorrow night driven by the mid-upper jet and a shortwave moving across the Great Lakes will support the next chance at showers and thunderstorms. The after midnight arrival will carry some uncertainty in regards to the severe weather potential. However, models want to hang on to instability during the arrival as bulk shear values also increase with improving mid-level lapse rates. Latest SPC Outlook has expanded the Marginal Risk for severe weather through all of southeast Michigan with a sliver of Slight Risk across the far northwest portion of the CWA. Damaging winds and brief heavy downpours are forecast to be the main threats.

Trailing cold front during the day Tuesday will keep a chance for showers and possible thunderstorms during the early afternoon as a secondary shortwave drops through the central Great Lakes. Any organized convection during this time frame will depend on how the morning activity plays out and if there is enough instability that is able to redevelop in the wake of morning convection. Passage of the cold front will bring a noticeable drop in temperatures for Wednesday with 850mb temperatures that fall to below 10C. The result will daytime high temperatures in the low to mid 70s. Surface high pressure should keep conditions mostly dry Wednesday into Thursday with a chance for light spotty showers along a frontal boundary being pushed south by an eastern Canada trough.

MARINE...

Post-frontal high pressure builds back into the central Great Lakes today supporting drier conditions and a return to prevailing winds below headline criteria through the rest of the weekend. Unsettled conditions may develop late Monday and Monday night, as a strong low pressure system tracks across central/southern Ontario. Gusty winds ahead of the attendant front may lead to a period of Small Craft Advisory conditions, particularly across Saginaw Bay where southwesterly flow could channel more efficiently. Potential for showers and thunderstorms increases across the waterways with this system, leading to periods of locally higher winds and waves. Showery weather could persist into Tuesday before high pressure from Manitoba builds in Tuesday night or Wednesday.

DTX WATCHES/WARNINGS/ADVISORIES

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