FORECAST SUMMARY:
Friday, September 25th, 2020 through Monday, September 28th, 2020
OZONE: 8-hour average Ozone concentrations are expected to be mostly Good; some Moderates are possible Friday or Saturday.
PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to middle Moderate.
FORECAST DISCUSSION:
A frontal boundary lingering over the northern portion of the state keeps clouds and precipitation in the forecast. Further south, summer-like conditions are in store as we end the week. Warm southerly winds will produce above normal temperatures and partly to mostly sunny skies prevail though Saturday afternoon. A cold front approaching by Sunday brings increasing clouds late Saturday and chances for precipitation Sunday afternoon/evening. Looking at the smoke plume analysis, smoke is lingering across the southern portion of the state. Smoke will likely linger over parts of the region this weekend; however, the smoke layer will be pushed out early next week.
As for air quality, fine particulate levels have been upper Good to low Moderate since Tuesday, and ozone has been mostly Good with only one monitor in the southwest reaching just over the Moderate threshold Wednesday, and four locations in the southeast Thursday. Fine particulate mostly in the Moderate range is likely across the southern portion of the state Friday and Saturday with Good levels up north. For ozone, southerly winds and warmer temperatures are conducive for increasing levels. Plenty of sunshine Friday will provide the best chance for Moderates as increasing clouds Saturday into Sunday should hamper ozone development. Also, the earlier sunset this time of year will help as ozone will not have as much time to develop. On Sunday, Good ozone is expected while any Moderate fine particulate should improve late in the day.
EXTENDED FORECAST:
Extended forecast models show unsettled weather developing next week with chances for precipitation and a drop in temperatures. This set-up will provide Good air quality.
Forecast update by Stephanie M. Hengesbach September 25th, 2020
Next forecast update: Monday, September 28th, 2020