…HEAT ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING… …HEAT ADVISORY IN EFFECT FROM 1 PM TO 8 PM CDT FRIDAY… The National Weather Service in Sioux Falls has issued a Heat Advisory, which is in effect from 1 PM to 8 PM CDT Friday. * HEAT INDEX VALUES…Up to 104 due to temperatures in the mid 90s, and dewpoints in the lower 70s.