168 million in 31 states suffering from oppressive heat

About half the country is under active heat advisories again on Tuesday, affecting more than 168 million Americans, according to the National Weather Service. 

The extreme heat continues in the Midwest, the Southeast and some parts of the Northeast. The heat alerts will remain in effect through Thursday in some places.

Temperatures on Tueday are forecast to be in the high 90s for multiple cities with feels-like temperatures over 100 degrees — in some areas, feeling like 110 or higher.

Extreme heat warnings also were issued in the country’s center from New Orleans up to St. Louis. The heat index value on Tuesday was expected to reach as high as 110 F around the St. Louis area and in southwest Illinois.

Some areas of the Great Plains and Midwest also face severe storm threats on Tuesday, potentially affecting cities including Chicago, Milwaukee, Denver, Omaha and Lincoln, Nebraska, Des Moines and Sioux City, Iowa, and Billings, Montana.

Health-related illnesses can increase significantly during extreme heat. It's advised to drink plenty of water and stay in air-conditioned rooms, meteorologists said.