The heat index could get as high as 111, with the strongest heat expected along the southern Gulf Coast. Southwest Florida won't be much better, with a heat index ranging between 100 and 107.

Forecasters have issued a heat advisory for Friday in Miami-Dade, Broward and Palm Beach counties, with temperatures expected to feel like 105 to 111 degrees. The advisory is in effect from 11 a.m. to 6 p.m.