PIERRE, S.D. (AP) — Much of the central U.S. is expected to swelter this weekend thanks to the hottest weather of the year.

Forecasting service AccuWeather says temperatures from Texas to the Dakotas and east into Ohio, Kentucky and Tennessee will climb high enough to create dangerous conditions for people who stay outdoors for long periods of time.

Temperatures are expected reach into the 90s and low 100s, and possibly set records in some areas.

Accuweather Senior Meteorologist Alex Sosnowski says Minneapolis, Indianapolis, Chicago, Cincinnati, Ohio, and Nashville, Tennessee, all are expected to have their hottest days of the year so far.

The National Weather Service says severe thunderstorms also are possible in the Northern Plains, the Great Lakes region, including Michiana, and the Northeast.

State officials have issued an ozone advisory for some of Indiana’s urban areas due to poor air quality.

The advisory covers Elkhart and St. Joseph counties, central Indiana, the Indiana suburbs of Louisville, Kentucky, and southwestern Indiana.

The Indiana Department of Environmental Management says levels of ozone, a powerful lung irritant that’s the main ingredient in smog, will be high through at least Sunday.

The agency says elderly residents, children and anyone with heart or lung conditions should reduce their physical exertion if they live in some urban areas.