FORECAST SUMMARY:
FORECAST SUMMARY: Friday, August 20th, 2021 through Monday, August 23th, 2021
Ozone: 8-hour average Ozone concentrations are expected to be mostly Moderate Friday and Saturday with isolated chances for USG; readings early next week will be between Good and Moderate.
PM-2.5: 24-hour average Fine Particulate concentrations will be in the upper Good to middle Moderate range.
FORECAST DISCUSSION:
Summerlike conditions will linger into the weekend with sunny skies, warmer temperatures, and increased humidity. Isolated afternoon storms could be seen Friday, but most locations will remain dry. A weak front coming through later Saturday will bring in another small chance for precipitation. High pressure moves on Sunday, but temperatures behind the Saturday boundary do not significantly decrease.
As for air quality, high pressure is dominating conditions Friday with lighter winds from more of a southerly direction. Ozone has been slowly increasing the past few days and that trend is expected to continue through Saturday. Readings haven’t reached higher low Moderate through Thursday, but more widespread Moderate ozone is anticipated both Friday and Saturday. There is a chance a monitor or two could reach low-end USG either Friday or Saturday with the best chances along the west Michigan lakeshore and in the southeastern portions of the state. However, upper-level temperatures haven’t increased significantly, and dew points remain high the next few days; both should assist in hindering a significant increase in ozone concentrations that would warrant an action day. Behind the Saturday front, ozone Sunday and Monday should fall back into the Good to Moderate range.
Fine particulate has been mostly Moderate across the state and this trend is expected to continue into early next week. We do get into a lighter northerly flow after the Saturday boundary passes which could allow smoke to move back over our region. This is something we will keep an eye on, but if this happens, smoke could keep Moderate fine particulate in place through early next week.
EXTENDED FORECAST:
Extended models show warmer temperatures and dry conditions going into next week. This will allow Moderate levels of ozone and fine particulate to continue.