FORECAST SUMMARY:
Tuesday, July 2nd, 2019 through Wednesday, July 3rd, 2019
...AIR QUALITY ACTION DAY ADVISORY FOR WEDNESDAY JULY 3RD IN SOUTHEAST MICHIGAN: LENAWEE... MACOMB... MONROE... OAKLAND... ST. CLAIR... WASHTENAW... AND WAYNE COUNTIES
Ozone: 8-hour Ozone concentrations will range between Good and Moderate, with scattered USG possible.
PM-2.5: 24-hour Fine Particulate concentrations will range from upper Good to middle Moderate.
FORECAST DISCUSSION:
The warm, muggy conditions will continue through the July 4th Holiday as will chances for scattered storms each day. This threat for storm development continues to make the air quality forecast a bit difficult. Ozone levels have been steadily increasing, especially in the southeast, and without a front/system to clean out conditions, this increase will likely continue. Forecast models show less in the way of clouds in the southern portion of the state both today and tomorrow. Ozone will be Moderate Tuesday, and isolated USG is possible in areas that have more in the way of sunshine.
For Wednesday, there will be some clouds, but they will be higher clouds which will allow for sunlight to go through. Storm chances are not great and without an airmass change there is enough risk for USG ozone in the southeastern portion of the state to warrant an Air Quality Action Day. Scattered USG could also be seen in the southwest, but clouds should be more prevalent keeping ozone generally Moderate.
Looking ahead to the July 4th Holiday, more in the way of cloud cover is expected along with higher chances for storms. At this time, it doesn’t look like we’d need to continue the Action Day into Thursday; however, conditions will be evaluated and the forecast will be updated tomorrow.
As for fine particulate, levels have been ranging from Good to Moderate and this trend will continue. Again, with the holiday approaching, remember that USG fine particulate levels will be likely in areas holding fireworks displays later this week.
EXTENDED FORECAST:
Ozone and fine particulate levels are expected to improve later in the week as a cold front finally brings back northwesterly winds. This airmass change should happen Friday into Saturday.