At least 100 Americans are on alert for dangerous heat and humidity -- stretching from Texas to Maine -- on Friday.

An intense heat wave threatens millions of people across the Southeast with temperatures reaching 115 degrees through midweek.

More than 100 million Americans are under heat alerts as the extreme temperatures that have smothered the Midwest this week arrive on the East Coast.

Much of the U.S. is under extreme heat warnings or advisories while New York, Philadelphia and Washington could feel like 100 degrees or more.

A Heat Advisory remains in effect with heat indices ranging from 100 to 110 degrees, and temperatures are expected to continue to rise until a cold front brings a cooldown on Wednesday night.

KNOXVILLE, Tenn. (WVLT) - Your weekend will come to a close with heat, humidity and a few of you will have an isolated downpour. Make sure you have the WVLT First Alert Weather app for iPhone or Android to get the latest updates on the intense heat.

Summer heat just got turned up a notch − and trapped under a lid. About 100 million people will see 100-degree days the rest of the week.