FORECAST SUMMARY:
FORECAST SUMMARY: Monday, July 19th, 2021, through Thursday, July 22nd, 2021
Ozone: 8-hour average Ozone concentrations are expected to be Good to Low Moderate.
PM-2.5: 24-hour average Fine Particulate concentrations are expected to be mostly Low to Mid-Moderate throughout the forecast period.
FORECAST DISCUSSION
Air Quality for last week was really Good for ozone concentrations, which is very nice to see this time of year. Fine particulates, however, ran well into the Moderate range, in many areas, due mostly to atmosphere transport smoke from numerous large fires in the western United States and Canada.
This week will start off similarly. For the first half of the week, ozone should be held at bay with northwesterly airflow. A pooling of ozone is expected over the bottom of Lake Michigan and perhaps some higher numbers could occur in the very southwest corner of the state if it bleeds inland. The fire and smoke maps are showing coverage over almost the entire 48 lower contiguous states. Only the very southeast and southwest corners of the country appear smoke-free. This will help lower ozone numbers as effectively as a cloud cover. But as some of that smoke mixes down to the surface, the monitors will reflect that in PM-2.5 creep. The fine particulate numbers will be similar to last week with concentrations ranging from Low Moderate to Mid-Moderate.
As high pressure slips eastward during the first half of the week, Expect a wind shift by late Thursday to the southwest. With that shift comes the ozone forming pollutants from Illinois/Indiana and Southeast Michigan. Because of that, the forecast will be updated on Thursday to reflect expected weekend conditions.
EXTENDED FORECAST
Air Quality is expected to be mostly Low Moderate going into the weekend.
Forecast updated by Jim Haywood: Monday, July 19th, 2021