FORECAST SUMMARY:
Friday, August 27th, 2021, through Saturday, August 28th, 2021
Ozone: 8-hour average Ozone concentrations are expected to be Good to Moderate, with a chance of USG on Saturday along the central West Michigan shoreline and northeast of Detroit.
PM-2.5: 24-hour average Fine Particulate concentrations are expected to range from Good to Moderate.
FORECAST DISCUSSION
Thursday’s forecast held fast as only a few Moderates were reported in West Michigan and the rest of the state was Good. Friday will have similar numbers.
Saturday looks to potentially have a different outcome. Temperatures and humidity will be high and southwest winds will likely push high ozone concentrations onto the shore along Lake Michigan and also northeast of Detroit. Although the cloud models are still showing mostly cloudy skies during Saturday, it has been performing poorly during the week and strong lake breezes have cleared the skies along the lake shores where we typically have high ozone issues.
All the better ozone models are being consistent and showing large pockets of high ozone in our most susceptible areas during Saturday. As a result, advisories are being issued in both West Michigan and SE Michigan for Saturday.
Sunday is still uncertain. An approaching cold front will pass through the state Sunday night and the timing of the front and associated approaching clouds will make all the difference in ozone production. Rather than rely on Friday’s forecast model, the model will be reviewed on Saturday to run the latest models.
As a result, the forecast will be revisited Saturday morning and updated for the Sunday forecast, at that time.
EXTENDED FORECAST:
Air Quality is expected to be Good to Moderate on Friday and ranging between Moderate and USG during Saturday. Sunday has yet to be determined.
Forecast updated by Jim Haywood: Friday, August 27th, 2021. Next forecast update: Saturday, August 28th, 2021