FORECAST SUMMARY: Monday, June 8, 2026 - Tuesday, June 9, 2026
Ozone: 8-hour average Ozone concentrations in the Good (AQI Green) to Moderate (AQI Yellow) range are expected.
PM-2.5: 24-hour daily average Fine Particulate concentrations will average between Good and low-Moderate.
FORECAST DISCUSSION:
High pressure will dominate central and eastern sections of the region to start the week, while an approaching system spreads increasing cloud cover across the west and brings precipitation to central and western portions of the Upper Peninsula. With a low background pollution level and southeasterly flow in place, ozone concentrations are expected to remain in the Moderate range on Monday. A developing low pressure system will move through on Tuesday, producing showers and thunderstorms across most areas. Abundant moisture will support periods of heavy rainfall within the stronger storms. In the system’s wake, southwesterly winds will usher in a hot and humid airmass for Wednesday and Thursday. While there is some uncertainty regarding storms mid‑week, the environment appears favorable for thunderstorm development.
Fine particulate levels early Monday are generally running in the Good range. Increasing moisture through the day should allow fine particulate concentrations to increase; however, daily averages are not expected to exceed the lower end of Moderate. With more sunshine expected across central and eastern areas on Monday, ozone may also climb into the Moderate category. On Tuesday, widespread clouds and precipitation should keep ozone mostly in the Good range. However, some model guidance suggests the southwest corner of the state may clear out on Tuesday. If that occurs, Moderate ozone would be possible in that area.
A muggy southwest flow will be in place from Wednesday into Thursday, and periods of thunderstorms are expected across the region. Current forecast models suggest a break in storms during the day Wednesday, with at least some clearing possible. The combination of warm surface and upper‑level temperatures, along with a southwest flow, is generally supportive of ozone development. However, dew points are forecast to be in the 70s, and moisture levels that high typically suppress ozone formation. While ozone is not expected to exceed the Moderate category, conditions are marginal enough that the setup warrants another evaluation on Tuesday.
EXTENDED FORECAST:
Moderate air quality could persist at times through the extended period.
Next Forecast update: Tuesday, June 9, 2026