Milwaukee, Ozaukee, Racine, Kenosha and Sheboygan are all under a poor air quality alert from noon to 11 p.m., according to the National Weather Service. The air quality index is expected to reach the "unhealthy for sensitive groups" to even the generally "unhealthy" level throughout the afternoon and evening, NWS says.

Sensitive groups are advised to stay indoors and limit outdoor activities as pollution and ozone levels spike to unhealthy levels due to smoke from Canadian wildfires.