FORECAST SUMMARY: Friday September 5th, 2025, through Monday September 8th, 2025
Ozone:
Ozone concentrations are expected to be in the Good (Green 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:
A breezy Friday morning and afternoon will kick off the first weekend of September with surface temperatures ranging from the upper-50s to mid-60s throughout the weekend. A Low-pressure system started to traverse across the Great Lakes region early Friday morning and is the reasoning behind the breezy conditions. The gradient of pressure within the atmosphere as the Low-pressure moves through is being compressed, which in turn produces windy conditions with the possibility of strong gusts. After all, wind speed and gusts are directly correlated with how tight the pressure gradient is within the atmosphere.
Going into Saturday, winds will continue to slow down as the aforementioned Low-pressure moves further east, and the skies will open up to more sunshine. Even though it is not astronomical Fall, it is technically meteorological Fall, and it very much will feel like Fall Saturday and into Sunday with highs in the mid-60s at best. Sunday will essentially be a copy and paste of Saturday with light to moderate winds. Due to the cooler temperatures and wind direction being predominantly west-northwesterly, lake-effect pop-up rain showers should be expected throughout the weekend as well. Just like lake-effect snow, the lake waters are warmer than the surrounding air, so the same mechanism of lake-effect snow takes place, but in this case, the surface air is still in the 50s and 60s, so precipitation will fall in the form of rain. As said above though, these will be sporadic and should not last long.
For air quality, the cooler temperatures will continue to keep Ozone concentrations at bay as we are closing in on the end of the Ozone season. For PM-2.5, a small and rather light plume of smoke is currently in the Midwest this Friday morning as monitors across the region are reading in the Moderate range. With the windy conditions in place, this plume will move out rather quickly. Throughout the rest of the weekend, however, Good PM-2.5 concentrations are expected with the exception of early morning light winds allowing for particulate build up in the more populated areas of metro Detroit and Grand Rapids.
EXTENDED FORECAST:
Temperatures return to the 70s next week with a small possibility of some wildfire smoke returning, but nothing more than Moderate concentrations as of right now. Air quality will be in the Good to Moderate range.
Next Forecast update: Monday September 8th, 2025