Pollutant Overview
Ozone (O₃):
8-hour average ozone concentrations are expected to range from Good (Green AQI) to Moderate (Yellow AQI). A small chance for Unhealthy for Sensitive Groups (Orange AQI) exists, particularly in southern areas.
Fine Particulates (PM-2.5):
24-hour average concentrations will be mostly Moderate (Yellow AQI) statewide, with some influence from surface-level smoke.
Forecast Discussion
Two key features are shaping Michigan's weather between Tuesday and Wednesday:
A high-pressure system positioned east of the state will keep conditions mostly quiet.
A frontal boundary to the northwest will begin bringing precipitation to the western Upper Peninsula later Tuesday. This front will slowly move south through Thursday, eventually impacting the Lower Peninsula with potential rain and storms.
In the meantime, temperatures will climb into the 80s and 90s, and humidity levels will rise, creating more uncomfortable outdoor conditions as the week progresses.
As for air quality:
Fine particulate levels (PM2.5) will remain mostly Moderate, as lingering smoke from Wisconsin and Lake Michigan shifts back over the region. No significant spikes are expected.
Ozone concentrations may also increase slightly due to this smoke, but rising dew points will likely help limit formation. A small chance for USG ozone levels exists in southern Michigan, though Good to Moderate conditions are expected across most areas.
Extended Outlook
Smoke model data suggests another potential smoke intrusion behind the frontal boundary on Thursday, which could impact air quality later in the week.
There remains uncertainty in the extended forecast regarding:
Timing of precipitation
Duration of lingering heat
Potential for wildfire smoke return
Future updates will provide more detail as conditions develop.