FORECAST SUMMARY: Saturday, July 12, 2025 - Sunday, July 13, 2025
Air Quality Alert for fine particulate begins at noon on Saturday, July 12 for the western Upper Peninsula, expanding statewide on Sunday, July 13 through noon Monday, July 14.
Saturday Alert Counties:
Baraga, Dickinson, Gogebic, Houghton, Iron, Keweenaw, Marquette, Ontonagon
Sunday–Monday Alert:
Statewide
Ozone:
8-hour ozone concentrations are expected to range between Good (Green AQI) and Moderate (Yellow AQI).
PM-2.5:
Saturday: Daily average fine particulate concentrations expected to range between Very Unhealthy (Purple AQI) to Unhealthy (Red AQI) in the western Upper Peninsula, with levels remaining mostly Moderate elsewhere.
Sunday: Concentrations will range from Very Unhealthy to Unhealthy in northern Michigan to USG (Orange AQI) and Moderate in southern regions.
FORECAST DISCUSSION:
A cold front will move through the region on Saturday, bringing chances of showers and storms. Behind the front, high pressure will build in on Sunday, ending precipitation from west to east. Warm, dry conditions are expected into the start of the workweek.
The primary air quality concern is elevated PM-2.5 levels from wildfire smoke moving down from Canada. Current smoke models show a concentrated plume entering the western Upper Peninsula by Saturday afternoon, moving across the U.P. and into Lower Michigan from late Saturday through Sunday.
As this occurs, elevated PM-2.5 concentrations are anticipated statewide. Based on model trends:
Very Unhealthy to Unhealthy levels are expected across the Upper Peninsula and northern Lower Michigan.
Unhealthy to USG levels in central portions of the state.
USG to Moderate levels further south.
Forecast updates will continue, with the next one scheduled for Sunday morning, which will also assess whether the air quality alert needs to extend beyond noon on Monday.
Looking ahead, ozone may become a concern into early next week, as southerly winds and warmer conditions return. This will also be reviewed in the next update.
EXTENDED FORECAST:
Dry, warm weather continues into next week. Conditions may support elevated ozone and/or PM-2.5 levels later in the period. Updates will be provided as needed.
Next forecast update: Sunday, July 13, 2025