FORECAST SUMMARY: Wednesday July 1st, 2026, through, Thursday July 2nd, 2026
Ozone:
Ozone concentrations are expected to be in the Moderate (Yellow AQI) range.
PM-2.5:
PM-2.5 concentrations are expected to be in the Moderate (Yellow AQI) range.
FORECAST DISCUSSION:
Michiganders are roughly halfway through this current heatwave as we wake up this Wednesday morning. Heat indices are expected to range from 100 degrees to even 110 degrees in some areas this afternoon and evening as surface temperatures remain in the mid to upper 90s and dew points well into the 70s. With these high dew points, we have observed the impact that very moist air can have on surface-level Ozone so far this week as Ozone has behaved for the most part. Both Monday and Tuesday this week have seen mostly Good Ozone concentrations where if conditions with lower dew points were in place, those same concentrations would be expected to be higher. High dew points and Ozone do not mix well, as mentioned in previous forecast updates, and it possibly could be attributed to the amount of increased moisture in the air scattering solar energy enough to hinder the Ozone photochemical reaction. Also, with the increased moisture, cloudy conditions are more likely to pop up to haze the sunlight. This is where forecast models and model guidance sometimes fail to produce accurate outputs with the previous days’ model guidance showing widespread Unhealthy for Sensitive Groups level Ozone across the state. As mentioned prior, Air Quality Alerts were in place, however, to err on the side of caution because although high dew points and low Ozone have been observed in the past, it is not always a guarantee.
Moving into later today, Wednesday, and tomorrow, Thursday, the heat wave continues with Good to Moderate Ozone expected across the state. PM2.5 is on the increase as was mentioned in previous updates, due to southerly flow and the increase in moisture. Thursday will see a slight decrease in concentrations due to the wind direction becoming slightly more westerly and additional rainfall in the north, which will help to clean the air. As we go into the 4th of July weekend, however, as with every year, firework displays will locally increase PM2.5 concentrations, especially if winds become lighter. The two previous years saw a rapid increase in PM2.5 concentrations in the metro Detroit area on the 4th of July due to fireworks, but those years also had rather stagnant conditions. As of now, this year looks to have enough wind to aid in dispersing PM2.5, along with scattered showers, but concentrations will be monitored because increases in concentrations are expected regardless.
EXTENDED FORECAST:
Hot temperatures remain through the weekend, although there is some relief as we get into Sunday. Air quality will be in the Moderate range due to increases in PM2.5 from fireworks displays.