FORECAST SUMMARY:
Wednesday, July 1st, 2020 through Thursday, July 2nd, 2020
OZONE: 8-Hour average Ozone concentrations will be mostly Moderate with a chance of isolated USG during Wednesday and Thursday. Air Quality may decrease over the course of the week.
PM-2.5: 24-hour average Fine Particulate concentrations will be mostly Good to Low Moderate through the week.
FORECAST DISCUSSION
The weather remains hot, humid, and sunny for the week and is expected to continue through the holiday weekend. Interesting enough, even though we remain in the same air mass under intense sun, there has been little variation in the ozone concentrations over the past two days. Along the West Michigan lake shore, inland monitors decreased during Tuesday while coastal monitors remained the same or slightly increased. In all cases, we have yet to see a USG concentration, this week.
The computer ozone models, for the most part, are staying with consistent ozone concentrations for midweek. Only one model is showing a spike for Thursday while all the other models are showing status quo or a slight decrease. All weather models are showing a shift of winds to a northerly component, at all levels of the atmosphere, during Thursday. This does not mean we will get any relief from the temperatures or humidity because we stay in the same air mass. But it does mean the winds will not be pushing pollutants towards us from the high pollution urban areas.
As a result, the forecast is in the Moderate range. Considering the time of year and the current weather conditions, however, it is never totally out of the question that some isolated spots could cross into the USG zone. If that happens, we will update the AirNow forecast map to reflect that change.
EXTENDED FORECAST:
Air Quality will stay mostly Moderate and perhaps an isolated USG during the latter half of the week.
Forecast updated by Jim Haywood: Wednesday, July 1st, 2020
Next forecast update: Thursday, July 2nd, 2020