FORECAST SUMMARY:
Thursday, June 18th, 2020 through Friday, June 19th, 2020
OZONE: 8-Hour average Ozone concentrations will be mostly Moderate and USG during Thursday and Friday. Both days have Air Quality Air Advisories.PM-2.5: 24-hour average Fine Particulate concentrations will be mostly Good to Low Moderates through the week.
AN ACTION DAY ADVISORY IS ISSUED FOR FRIDAY FOR THE FOLLOWING MICHIGAN COUNTIES...
ALLEGAN... BENZIE… BERRIEN… CASS… GRAND TRAVERSE... KALAMAZOO… KENT... LEELANAU… MANISTEE… MUSKEGON... OCEANA… OTTAWA… MASON… St. JOSEPH… AND VAN BUREN COUNTIES IN WEST MICHIGAN; AND
GENESEE… LAPEER… LIVINGSTON… MACOMB… MONROE… OAKLAND… ST. CLAIR… WASHTENAW… AND WAYNE COUNTIES IN SOUTHEAST MICHIGAN
FORECAST DISCUSSION
Moderates and USG levels dominated the Air Quality map during Wednesday. I was a bit surprised as to how quickly some of the monitors jumped into the low USG level after starting the day with relatively low concentrations. That reinforces the decision to issue air advisories for Thursday. As conditions can only get worse, we will be continuing advisories into Friday and expanding the list of counties.
We remain under the same air mass with increasing temperatures and humidity. Air pollutants are accumulating because they have nowhere to go and the high pressure dome are keeping them suppressed at the surface.
We will not be out of the woods after Friday as we will be in the same air mass through the weekend. However, there may be some clouds and showers during the weekend in advance of a frontal passage Monday or Tuesday. If that occurs, it would help keep concentrations down but it may not be widespread enough to really make a difference. The Friday forecast will shed more light on that.
EXTENDED FORECAST:
Air Quality should remain Moderate to USG going into the weekend.
Forecast updated by Jim Haywood: Thursday, June 18th, 2020
Next forecast update: Friday, June 19th, 2020