FORECAST SUMMARY: Friday, May 30, 2025 - Saturday, May 31, 2025
Ozone: 8-hour ozone concentrations are expected to range between Good (Green AQI) and Moderate (Yellow AQI).
PM-2.5: 24-hour daily average Fine Particulate concentrations will average between Moderate and USG (Orange AQI).
Air Quality Advisory for Michigan starting Friday (May 30th) until 6 am Saturday (May 31st)
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) has issued an Air Quality Advisory for elevated levels of fine particulate (PM2.5) across the state of Michigan. Pollutants across the state expected to be in the Unhealthy for Sensitive Groups (USG, Orange AQI) range Friday into Saturday morning.
The Air Quality Advisory includes all Michigan counties.
FORECAST DISCUSSION:
The Air Quality Advisory issued yesterday for the western Upper Peninsula has been expanded to cover all of Michigan. Forecast models Friday morning are consistent with showing a cold front moving down from Ontario Friday, bringing in smoke plumes from wildfires in the provinces of Manitoba and Saskatchewan. The smoke plumes, along with the associated increase in PM2.5 levels, will move from north to south across the state from Friday morning until Saturday morning. Increased vertical mixing associated with the boundary will likely bring smoke to the surface. As a result, we anticipate PM2.5 levels rising into the Unhealthy for Sensitive Groups (USG) range across the state. There is a possibility that hourly levels could reach the Unhealthy (Red AQI) range for a short period of time. While not all locations will experience USG levels, it would be hard to pinpoint exact locations, and the threat seems to be widespread enough to warrant the statewide advisory.
Increased levels of fine particulate were being seen early Friday in the western portion of the Upper Peninsula, and increases will spread south as the day progresses. The frontal boundary clears the state Saturday morning, and winds switching to a north/northeast direction will push the smoke south and west of the state. Some lingering smoke could allow for a continuation of Moderate fine particulate on Saturday, especially in southern areas.
For ozone, clouds associated with the Friday front and northerly winds on Saturday should hamper any significant development. Readings of ozone are not expected to reach higher than Moderate.
EXTENDED FORECAST:
There is a possibility that smoke returns to the region late in the weekend. Since there is a lot yet to be determined for early next week, this forecast will be updated Saturday morning.
Next Forecast update: Saturday, May 31, 2025