07/01/2019 Forecast Update


Monday, July 1st, 2019 through Tuesday, July 2nd, 2019

Ozone: 8-hour Ozone concentrations will range between Good and Moderate, with isolated USG possible.

PM-2.5: 24-hour Fine Particulate concentrations will range from upper Good to middle Moderate.


Warm, muggy conditions will be noticed this week and chances for scattered storms exist each day. Not all areas will see precipitation, however, and this makes the air quality forecast a bit tricky. For today, clouds are not expected to be as prevalent as weekend forecast models were making conditions out to be. Therefore, ozone Monday may be higher than expected to where isolated monitors in the west and/or southeast could get into the low-end USG range. Otherwise, mostly Moderate levels will persist.

Looking ahead to Tuesday, a boundary is expected to be positioned across the southern portion of the state. It does look like more clouds will be overhead compared to Monday which should hamper significant ozone development. The flip side to that is, ozone may increase quickly in areas that have more in the way of sunshine. Overall, clouds and increased chances for afternoon/evening storms will keep ozone from reaching higher than Moderate.

Tuesday’s chances for precipitation look a bit higher than Wednesday so the threat for increased ozone could continue. With so much uncertainty in the forecast, the regional forecasters are having another call Tuesday morning to determine expected conditions for Wednesday.

As for fine particulate, with increased moisture and a boundary lingering across the state, Moderate levels are expected. With the July 4th holiday a few days away, make note that USG fine particulate levels will be likely in areas holding fireworks displays later this week.


Ozone and fine particulate levels are expected to improve later in the week as a cold front finally brings back northwesterly winds. This airmass change should happen Friday into Saturday.

Next forecast update: Tuesday, July 2nd, 2019
Forecast by: Stephanie M. Hengesbach, Meteorologist, Air Quality Division, Michigan Department of Environment, Great Lakes, and Energy