The National Weather Service has issued heat advisories for the southeastern United States. It's always hot in the summer in the U.S. Southeast, but even by the standards of Florida and the Carolinas, the steamy heat wave on tap for the region Saturday into the coming week is a little extreme.

Around 100 million people are under heat alerts Friday, from coastal Maine to South Carolina and across much of the Midwest and lower Ohio Valley into the Mid-South. Additional alerts are likely in the Southeast as temperatures rise in coming days.