FORECAST SUMMARY:
Friday, August 13th, 2021, through Monday, August 16th, 2021
OZONE: Ozone concentrations are expected to be mostly Good for the upcoming weekend and into early next week.
PM-2.5: PM-2.5 concentrations are expected to be Good for the weekend and into early next week.
FORECAST DISCUSSION:
Upper-level winds will mainly be from the WNW for most of the weekend. An approaching High-pressure system from the west will shift these winds to a more northwest flow going into Sunday. Upper-level temperatures are expected to be in the upper teens Celsius today, Friday, but are expected to drop to the low-to-mid teens Celsius for the rest of the weekend. The combination of shifting winds and decreasing upper-level temperatures will help keep ozone concentrations at bay. There appears to be some ozone pooling over Lake Michigan, but it is forecasted to mainly stay offshore with the possibility of reaching the shoreline only for a short period of time.
After a long week of hot, humid surface temperatures, the region finally gets a break thanks to the cold front that made its way through today, Friday. Daytime dewpoint temperatures will drop to the low-mid 50s Fahrenheit and surface daytime temperatures will be in the low 80s Fahrenheit for much of the area. Surface winds will also be from the WNW for the weekend with a northerly shift going into Sunday as the High-pressure sets up over Lake Michigan. This High-pressure will help keep the weekend clear and dry. Surface PM-2.5 hasn’t been of much concern this week and it will continue not to be going into the weekend, as not much smoke has been mixing down towards the surface. Ozone concentrations will struggle to develop due to the decreasing upper-level and surface temperatures. As stated above, there will be ozone pooling over Lake Michigan with the possibility of reaching the shoreline, but not enough to put 8-hour averages into the Moderate range.
EXTENDED FORECAST:
Going forward into early next week, it is more of the same in terms of concentrations. The High-pressure moves off into Ontario but still provides us with clear skies and cooler temperatures compared to this past week.
Forecast updated by Alec Kownacki, Friday, August 13th, 2021. Next Forecast update on Monday, August 16th, 2021.