FORECAST SUMMARY:
Thursday, July 2nd, 2020 through Friday, July 3rd, 2020
OZONE: 8-hour average Ozone concentrations will be mostly Moderate with a chance for isolated USG Thursday and Friday. Air Quality may decrease as we move into the holiday weekend.
PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to middle Moderate through the weekend.
FORECAST DISCUSSION:
As we move towards the July 4th holiday, the weather remains hot, humid, and sunny. The air quality forecast remains consistent that even though we are still in the same air mass, there has been little variation in the ozone concentrations over the past few days. In fact, ozone levels in many locations were lower Wednesday than Tuesday, and we have yet to see a USG concentration this week.
The computer ozone models, for the most part, are staying steady with ozone concentrations. One model shows a spike Thursday and Friday right along the west Michigan lakeshore while all the other models are showing status quo or a slight decrease on Friday. After again evaluating the expected wind patterns, models still show winds from to a northerly component Thursday and Friday at all levels of the atmosphere. This does not mean we will get any relief from the temperatures or humidity, but it does mean the winds will not be pushing pollutants towards us from the high pollution urban areas.
As a result, the forecast remains Moderate for ozone Thursday and Friday. Considering the time of year and the current weather conditions, however, it is never totally out of the question that an isolated location could cross into the USG zone. If that happens, the AirNow forecast map will be updated to reflect that change.
Light winds and no air mass change has allowed for an uptick in fine particulate. With conditions not changing, and possibly localized fireworks displays over the next few days, fine particulate is expected to range from upper Good to mostly Moderate through the weekend.
EXTENDED FORECAST:
With so much uncertainty in the air quality forecast, we will continue with daily updates. For now, ozone is expected to remain mostly Moderate with perhaps an isolated USG moving into the weekend.
Forecast updated by: Stephanie M. Hengesbach
Next forecast update: Friday, July 3rd, 2020