FORECAST SUMMARY: Friday, September 12, 2025, through Monday, September 15, 2025
Ozone:
Ozone concentrations are expected to be in the Good (Green AQI) to Moderate (Yellow AQI) range.
PM-2.5:
PM-2.5 concentrations are expected to be in the Good (Green AQI) to Moderate (Yellow AQI) range.
FORECAST DISCUSSION:
Fair weather clouds, mostly sunny skies and surface temperatures reaching the 80s is what Michiganders have in store for this Friday. High-pressure sits both to our northeast and southeast, providing warm and sunny conditions. The only real hindrance in the upcoming forecast is tomorrow, Saturday, with scattered to spotty showers possible for southern Michigan as a weak frontal boundary approaches the state, it will not be a complete washout, however. Surface temperatures will range in the mid-70s for the majority of the state, with overcast to partly cloudy skies throughout the day. Come Sunday, although, we are back under High-pressure with clearing skies and making a run at 80-degree temperatures across the state. Monday and into next week, this trend continues as warmer temperatures return to the Great Lakes.
For air quality, with surface temperatures reaching the 80s, coupled with light winds, Ozone may pose a threat with concentrations reaching the high-Moderate range in both southwest and southeast Michigan, with the possibility of an hourly concentration in the Unhealthy for Sensitive Groups (USG) range. These concentrations in the USG range should not be widespread, however. It is not uncommon for USG-level Ozone concentrations in the month of September, but decreasing sunlight and an unfavorable sun angle, makes it hard for Ozone to produce. With even warmer temperatures next week, Ozone will be looked at more closely. PM-2.5 concentrations will continue their trend of Good to Moderate concentrations, especially for more populated areas like Grand Rapids and Detroit. Southerly flow later this weekend may increase concentrations into the mid-Moderate range, but only for a few hours before decreasing.
EXTENDED FORECAST:
Summer-like temperatures return next week as the mid-to-upper 80s are on the horizon for areas across Michigan. Air quality, as of now, will remain in the Good to Moderate range.
Next Forecast update: Monday, September 15, 2025