FORECAST SUMMARY:
Thursday, August 26th, 2021, through Friday, August 27th, 2021
Ozone: 8-hour average Ozone concentrations are expected to be Good to Moderate, with a chance of isolated USG.
PM-2.5: 24-hour average Fine Particulate concentrations are expected to range from Good to Moderate.
FORECAST DISCUSSION
As discussed on Monday, ozone concentrations would be mostly Moderate in the susceptible areas unless we had pockets of prolonged sunlight. We had that occur northeast of Detroit on Tuesday as a lake breeze kept skies clear over the St. Clair County area. As a result, two monitors in that area went USG.
During Wednesday, the Holland monitor was stuck in a rich Chicago plume, under sunny skies, and went USG. Isolated pockets of poor Air Quality could continue to occur, which will necessitate continued close watching for the duration of the workweek.
The cloud models have performed poorly, all week, and still showing mostly cloudy skies Thursday and Friday. Smoke from Minnesota wildfires will likely drop south, on Thursday, for extra protection from the strong sun. It would be a surprise to see any USG although it is possible for isolated hotspots.
Friday doesn’t seem to carry a large threat with a better chance of clouds and showers due to a warm front over the area. The weekend outlook, however, is not as good. The models are showed persistent southwest winds, hot temperatures, high humidity, and ample sun in advance of a Sunday night cold front. It is a good possibility that we will see Action Day advisories, during the weekend, unless there is a change in tomorrow’s model results.
EXTENDED FORECAST:
Air Quality is expected to range between Moderate and USG going into the weekend.
Forecast updated by Jim Haywood: Thursday, August 26th, 2021. Next forecast update: Friday, August 27th, 2021