Wednesday, July 17th, 2019 through Thursday, July 18th, 2019
...AIR QUALITY ACTION DAY ADVISORY FOR THURSDAY JULY 18TH...
IN WEST MICHIGAN:
ALLEGAN... BERRIEN… CASS… KENT... MUSKEGON... OTTAWA… AND VAN BUREN COUNTIES
Ozone: 8-hour Ozone concentrations will range between Good and Moderate with USG possible in the west and southeast Thursday.
PM-2.5: 24-hour Fine Particulate concentrations will be in the Good to Moderate range.
The heatwave that has been forecast a few days now is ready to begin. Wednesday the region is still experiencing increased moisture, scattered clouds and small chances for precipitation from the remnants of what was Hurricane Barry. This system finally pulls out of the area; however, upper level ridging builds in Thursday bringing very warm surface and upper level temperatures. Humidity levels will also be increasing with heat indexes approaching or exceeding 100 degrees in many locations. As for air quality, when and where storms may develop is making the forecast tricky.
For Wednesday, partly sunny skies and winds with a northeasterly component should keep ozone in the Good to Moderate range. On Thursday, a storm complex is expected to develop over northern Wisconsin and track east early in the day. Current models keep this complex from slipping into the southern half of Lower Michigan. This means, sunshine will be more prevalent in the south and that, coupled with warm surface and upper level temperatures, and southwesterly winds, make increased ozone a good possibility. The threat is high enough to warrant Action Days for Thursday in both the southwest and southeastern portions of the state.
The threat for increased ozone could linger into Friday, therefore, the regional forecasters will talk Thursday morning to determine if the Action Day should be continued.
Fine particulate could also see slow increases the next few days with readings ranging from upper Good to lower Moderate.
Extended models show hot conditions lingering through most of the weekend. AQD forecasters will be keeping eye on conditions to determine if Action Days are needed over the weekend.