...HEAT ADVISORY IN EFFECT FROM NOON TODAY TO 7 PM CDT SUNDAY... * WHAT...Heat index values 104 to 109 expected. * WHERE...Portions of north central and south central Texas. * WHEN...From noon today to 7 PM CDT Sunday. * IMPACTS...Hot temperatures and high humidity will increase the risk for heat-related illnesses to occur, particularly for those working or participating in outdoor activities.