Punishing heat wave peaks as East Coast readies for sweltering July 4 weekend

A dangerous heat wave is tightening its grip on the East Coast, with the worst conditions arriving as millions prepare to celebrate the Fourth of July outdoors.

​ A dangerous heat wave is tightening its grip on the East Coast, with the worst conditions arriving as millions prepare to celebrate the Fourth of July outdoors. Read More Breaking News, Latest News and Videos | CNN