A large swath of the U.S. remains under active heat advisories again on Wednesday, affecting more than 140 million Americans, according to the National Weather Service. 

The extreme heat continues in the Midwest, the Southeast and some parts of the Northeast, though a cold front is moving through the north to cool things down there. Higher extremes are expected over most of the Southeast through the end of the week. 

New York City broke a record Tuesday afternoon, hitting 100 degrees Fahrenheit at La Guardia Airport. Tampa, Florida, which is usually cooled down by a sea breeze, hit a record high of 100 degrees on Sunday, local media reported.

Temperatures on Wednesday 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.

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.

Some areas of the Rockies, Midwest and Northeast also face a risk of severe storms on Wednesday, potentially affecting cities including Denver, Kansas City, St. Louis, Chicago, Indianapolis, and along the Eastern Seaboard from Pennsylvania to Maine.