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Noise monitoring program

Department meteorologists use monitoring data and weather forecast models to predict Wisconsin's future ozone (O3) and fine particulate matter (PM2.5) air quality using the Air Quality Index (AQI) [exit DNR]. This forecast is updated two-to-three times weekly throughout the year, and when warranted, an Air Quality Advisory is issued. Below is the latest air quality forecast for Wisconsin.

Friday, July 12 - Thursday, July 18, 2024

Ozone

Good to USG levels.

Particle pollution (PM2.5)

Good to Moderate levels.


Short-Term Forecast Maps:

Forecast AQI maps for the short-term forecast period.

The black dots represent the approximate location of Wisconsin's air quality monitors. Read the forecast summaries below for further geographic information.


Short-Term Forecast (Days 1-3)

PM2.5 concentrations remain slightly elevated Friday morning due to lingering smoke from Canadian wildfires. In general, this smoke should be lifting to the north and east today as flow becomes southerly to southwesterly. Although Low-Moderate AQI PM2.5 will remain possible statewide, we’ll forecast Low-Moderate AQI PM2.5 for northern and southwestern Wisconsin, with Good AQI PM2.5 forecast for southern and eastern Wisconsin. Along with southerly flow, mostly sunny skies and a lack of precipitation will encourage ozone production through the afternoon. However, we also anticipate vertical mixing to be robust, which should help limit ozone concentrations. We will forecast one more day of Good AQI ozone statewide, with a mention that areas of Low-Moderate AQI ozone remain possible, particularly across south-central and southeast Wisconsin. On Saturday, weak high-pressure will remain rooted over the eastern Great Lakes while an upper-level disturbance approaches Wisconsin from the west-northwest, possibly bringing a couple of rounds of precipitation including strong to severe potential Saturday evening into Sunday morning. Although Low-Moderate AQI PM2.5 will remain a possibility, we’re expecting a return to mostly Good AQI PM2.5, with the best chance for Low-Moderate AQI PM2.5 across eastern and northeastern Wisconsin. Ozone looks to be the more active pollutant come Saturday, with widespread Moderate AQI forecast. Current expectations are for USG AQI ozone to develop across southeastern Wisconsin counties caught in the lake breeze, with a potential for USG AQI ozone to develop along the lakeshore up through Door County. Sunday’s air quality forecast remains heavily conditional on the precipitation that moves through late Saturday into early Sunday. Current thinking is that this precipitation should be heavy and widespread enough to scrub the atmosphere, and along with a westerly flow developing behind the precipitation, should result in a mix of Good to Moderate AQI. That being said, USG AQI ozone cannot be ruled out for lakeshore counties if a lake breeze is able to develop and precipitation is more limited.

Extended Outlook (Days 4-7)

Another system is currently expected to move through on Monday, with the timing of the cold front and associated precipitation (potentially severe) likely playing a role in Monday’s air quality outcomes. A slower arrival will keep USG AQI ozone potential along the lakeshore, while an earlier arrival should mean a mix of Good to Moderate AQI ozone. Good AQI PM2.5 is likely to continue. Models are then showing that a transition is likely to begin Tuesday as the low-pressure system moves ENE towards Hudson Bay and a robust high-pressure air mass descends into the region from the Canadian Prairies. Currently, Good AQI ozone is expected to develop Tuesday and continue through Thursday. However, PM2.5 remains in question as we’ll need to see if any smoke associated with Canadian wildfires moves in with the high-pressure air mass. For now, we’ll keep a Good to Moderate AQI PM2.5 forecast Tuesday through Thursday, and closely monitor how Canadian wildfires and their smoke plumes evolve over the weekend.


Air Quality Index (AQI) ranges

For more information about AQI ranges and colors, see the U.S. EPA's Air Quality Index (AQI) Basics [exit DNR].