100-degree temps scorch large swaths of U.S.; more than 150 million people under heat alerts

Extreme heat will continue across much of the southern Plains to New England, with more than 150 million people under heat alerts.

Extreme heat will continue across much of the southern Plains to New England, with more than 150 million people under heat alerts.

Record temperatures are likely Tuesday across the Northeast and Florida, where the mercury could climb to the low-100s. Hartford, Connecticut; Newark, New Jersey; Tampa and Orlando in Florida; and Philadelphia are some cities that could see record highs.

Air quality alerts have also been issued from Rhode Island to Delaware.

"Be careful. Today is an air quality alert day meaning the air is unhealthy for sensitive groups," the New York City Department of Citywide Administrative Services said in a post Tuesday on X.

By Thursday, the heat will break for the Midwest, the Great Lakes and the Northeast. In the South, extreme temperatures are expected through the end of the week.