Current air quality outlook
Department meteorologists use monitoring data and weather forecast models to predict Wisconsin's future air quality using the Air Quality Index (AQI) [exit DNR]. If warranted, an Air Quality Notice is issued. Below is the latest air quality forecast for Wisconsin.
Monday, October 25 - Sunday, October 31, 2021
Particle pollution (PM2.5)
Good to Moderate levels.
Monday - We’re starting the week off with a gloomy and rainy morning, as a surface low-pressure system exits to the southeast of the state. Winds will be primarily from the northeast, with gusts in excess of 20 mph for locations along the lakeshore. The rather active weather pattern coupled with elevated wind speeds should allow for continued Good AQI.
Weather map for Monday, October 25, 2021. Graphic is courtesy of the NOAA/NWS Weather Prediction Center.
Tuesday - Mid-level ridging is expected to build through the overnight hours as a low-pressure system continues to exit the Midwest. This will produce clearing skies, increasing the likelihood that an early-morning surface inversion will develop. This could act to increase regional PM2.5 concentrations, with urban areas experiencing the largest impacts. If this occurs, any elevated PM2.5 concentrations will decrease as the inversion erodes after sunrise, keeping the overall AQI for the day in the Good to Low-Moderate range.
Weather map for Tuesday, October 26, 2021. Graphic is courtesy of the NOAA/NWS Weather Prediction Center.
Wednesday - Another round of precipitation is in store, as a deep mid-level disturbance will approach from the west. Western counties will be the first to see impacts from this system, with eastern counties more likely to see precipitation closer to the the evening and overnight hours. Ahead of this system, winds will shift to southerly – gusts may reach upwards of 15-20 mph, with the highest temperatures reaching the mid-to-upper 50s. Good AQI is expected to persist for most, with the potential for an inversion-driven PM2.5 maxima for central and eastern urbanized counties in the early-morning hours.
The system on Wednesday will continue to impact WI though Thursday. Precipitation will cease and skies will begin to clear Thursday night into Friday. High pressure looks to be the dominate forcing mechanism for the weekend, allowing for primarily clear skies and minimal chances for precipitation to persist through Halloween. With the clearing skies, enhanced PM2.5 concentrations associated with early morning surface-based inversions will remain possible. Overall AQI should remain in the Good range.
Note: All weather maps are courtesy of the NOAA/NWS Weather Prediction Center [exit DNR].
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].