FORECAST SUMMARY: Monday, October 7, 2024, through Friday, October 11, 2024
OZONE:
Ozone concentrations will be Good .
PM-2.5:
PM-2.5 concentrations are expected to be in the Good to low-Moderate range.
FORECAST DISCUSSION:
Unexpected hourly increases in PM2.5 concentrations were seen across the state on Sunday. These increases were caused by upper-level wildfire smoke being brought down to the surface behind a cold front that passed through. All monitors experienced hourly increases, with most locations reaching into the upper Moderate range; however, the increases only lasted a few hours, and daily averages remained low-Moderate. The highest increases in hourly concentrations were seen at our Grand Rapids area monitors, where readings reached the Unhealthy for Sensitive Groups (USG-Orange AQI) for a couple of hours. Like other areas, the increases were partly due to the upper-level smoke being transported to the ground, but more so they were influenced by area fires that developed in Ottawa County. The plumes from those fires were pushed east, towards the monitors. Those fires were put out during the day, with the increased PM2.5 concentrations only lasting a few hours.
For this week, Canadian high pressure sinking in will produce cooler fall-like conditions. A shortwave passing by northern locations early this week may kick off light precipitation; otherwise, dry conditions prevail under a northwesterly wind flow. By Friday, the high-pressure area weakens and moves east, allowing winds to turn more southerly. High temperatures this week will primarily be in the 60s, increasing towards 70 late in the week. Cool nighttime temperatures in the 30s to 40s can be expected, along with areas of frost some mornings.
Air quality conditions during the week are expected to average mostly Good, aside from a low-Moderate daily PM2.5 concentration mixing in. During the week, we will keep an eye on weather conditions along with any changes in expected smoke transport and/or local fire development that may occur. Updates will be made to this forecast if conditions change from what we currently expect.
EXTENDED FORECAST:
Extended forecast models show a boundary moving in from the north that may bring in a small chance for precipitation. Air quality in the long term should not be any higher than low-Moderate.
Next Forecast Update: Friday, October 11, 2024