FORECAST SUMMARY:
Friday, August 6th, 2021, through Monday, August 9th, 2021
Ozone: 8-hour average Ozone concentrations are expected to be Good to Moderate.
PM-2.5: 24-hour average Fine Particulate concentrations are also expected to range from Low to High Moderate.
FORECAST DISCUSSION:
Smoke continues to be an issue as our monitors still show concentrations higher than we normally see, but the 24-hour averages remain in the Moderate range. This will likely continue for the short-term future. The smoke models do have it thinning out over the weekend, but not going away. All indications are that we will continue to fare no worse than Moderate for our 24-hour averages.
We have been focusing most of our attention on the fine particulates brought to us by the wildfires out west and in Canada. But even though ozone production has been down lately, it is always a threat, and we cannot afford not to keep an eye on it. The computer models are indicating a buildup over southern Lake Michigan through the weekend. As with most of the computer ozone forecasts over the past few weeks, this is likely an overprediction with the smoke layer in the upper atmosphere reducing the sun’s power. Add the potential for hit or miss showers through the weekend, and the potential is even less. I expect the best chance of rain showers will occur Friday, Sunday, and Monday. Even without the showers, there should be enough associated clouds to discourage serious ozone production. Saturday looks to have the best chance for some prolonged sunlight, so we could see a creep in the numbers during the afternoon. But I do not see a strong indicator that any widespread USG readings are likely.
That said, we may have some ozone creep if we do have any areas of prolonged sun. If that happens, we could see some isolated spots of low USG, especially in the southern tier counties along Lake Michigan. I will be keeping an eye on conditions as they develop Saturday, and make any adjustments necessary to the forecast.
An upper-level system should bring in better chances for showers late Sunday through Monday. That will eliminate any ozone issues for late in the weekend and early next week. But the smoke will still be lingering, and we will continue to watch that.
EXTENDED FORECAST:
Air Quality is expected to range between Good and Moderate going into the next work week.
Forecast updated by Jim Haywood: Friday, August 6th, 2021