The heat wave that has blanketed a vast swath of the U.S. since early this month is now entering its third week, and it is intensifying in the Midwest before taking aim at the South and Southeast for the rest of the week.
The big picture: Combined with sultry levels of humidity at times, air temperatures in the low triple-digits will bring dangerous heat to cities including Nashville, Tennessee; Atlanta; Birmingham, Alabama; New Orleans; Houston and Dallas. Heat advisories were in effect for 42 million residents on Tuesday afternoon, from Michigan to New Orleans.
