Excessive heat warnings and advisories continue for sections of the central and southern Plains and into the Lower Mississippi Valley and Gulf Coast. 

IT'S SUMMER! PROTECT YOUR TECH FROM THE HEAT

Forecast heat index

The forecast heat index across the U.S. on Tuesday (Credit: Fox News)

High temperatures combined with humidity will make it feel well over 100 degrees for millions of people.  

Phoenix heat records

The longest 110-degree day streaks in Phoenix, Arizona (Credit: Fox News)

Strong-to-severe thunderstorms will be possible Tuesday for parts of the northern Plains.

Heat alerts across the South

Heat alerts forecast through Tuesday evening (Credit: Fox News)

CLICK HERE TO GET THE FOX NEWS APP 

Heavy rain and the risk of flooding will target sections of the mid-Mississippi Valley over the next few days.