FORECAST SUMMARY: Monday, may 29, 2023, through tuesday, may 30, 2023

OZONE:  8-hour average ozone concentrations are expected to be mostly high Moderate inland with the potential for USG along the lakeshore and Southeast Michigan.

PM-2.5: 24-hour average Fine Particulate concentrations are also expected to be mostly Good to Moderate through the forecast period.

FORECAST DISCUSSION:

In terms of weather, the forecast has not changed from yesterday’s forecast…  The current dry weather and increasing temperature/humidity regime will continue through most of the upcoming week with no rain in sight. 

So far, our Air Quality has been mostly Moderate except one monitor in the Thumb region reaching USG, yesterday.  Sunday’s temperatures finally crossed into the lower 80’s and will continue to increase, every day, this week.  Dew points have been dry, in the 40-50 degree range, but will begin to increase, Tuesday, as winds become more southerly.

The models have been indicating that our Air Quality should stay mostly in the high Moderate range.  However, the concentrations have been increasing, each day of this weather pattern, and most of the stations in the state fell only a few ppb short of reaching the USG threshold, yesterday.  As such, I will side with caution and issue an Action Day Advisory for Tuesday for both the lakeshore counties and Southeast Michigan.  On these marginal high ozone days, actions taken by individuals could mean the difference between crossing into USG or staying Moderate.

I will be monitoring our Air Quality, today, and if any of our monitor stations looks to exceed the USG threshold, I will update their status to trigger EnviroFlash notifications.

Since we will be under the same air mass until the weekend, I expect each day to be a little worse than the last with the increasing temperature, humidity, and stagnation.  We typically do not issue Action Day Advisories two days in advance, therefore we will revisit and update this forecast Tuesday morning. 

EXTENDED FORECAST:

Air Quality should be generally Moderate to USG through the work week.

Forecast updated by: Jim Haywood: Monday, May 29, 2023

Next Forecast update: Tuesday, May 30, 2023