Peak heat index forecast Friday, July 22. ( NOAA’s Hydrometeorological Prediction Center )

And poor Richmond, Va.! NOAA projects its heat index will soar to a stifling 118 degrees.

The picture above says it all. Just look at how much of the country is poised to reach heat index values of at least 100. (Remember that the heat index measures not the actual air temperature, but rather what it “feels like” due to the added influence of humidity).

Related: Heat wave and hot weather guide | Submit your hot weather photos

Thursday at 1 p.m.: Live video discussion about heat wave (send your questions now)