SUNDAY A.M. UPDATE: An extreme heat warning has been issued for much of Mid-Missouri, and for those not under an extreme heat warning, a heat advisory has been issued. The extreme heat warning, which will be the most likely area to exceed heat index values of 105 degrees, will be in effect from now until Wednesday at 8 P.M. Due to increased confidence that this heat will be lasting through Wednesday, the ABC 17 Stormtrack Weather Team has extended the ABC 17 Stormtrack Weather Alert Day, which will now come to an end on Wednesday, once the extreme heat warning expires. An ABC 17 Stormtrack Weather Alert Day has been issued from Sunday through Wednesday for a dangerous heat wave that will drive the heat index into the triple digits for several days. The heat index will soar to between 100 and 105 degrees each day from Sunday through Wednesday, having the best chance to exceed 105 on Monday and Tuesday. Take care during this heat wave by reducing strenuous outdoor activities, staying in the AC as much as possible, and drinking lots of water.