Full Episode: TODAY Show - Aug. 18

HI THERE. GOOD TUESDAY MORNING. DANGEROUS HEAT SURGING ACROSS MUCH OF THE COUNTRY.>> AND IT IS GOING TO STICK AROUND FOR A WHILE, TOO. IT IS AUGUST 18th. THIS IS "TODAY." STIFLING.TENS OF MILLIONS FACING RECORD-SETTING TEMPERATURES FROM THE SOUTHWEST TO THE MID-ATLANTIC TODAY. A HEAT INDEX ABOVE 110 ACROSS PARTS OF THE SOUTH. >> WHEN I GOT IN MY CAR, IT WAS READING 116.>> WHILE THE MIDWEST BRACES FOR A NEW THREAT OF FLASH FLOODS. WE'LL HAVE YOUR FULL FORECAST. >>> SEARCHING FOR ANSWERS.NEW DETAILS EMERG ...