Warmer weather is expected to push heat index values to around 105 degrees across the region today, prompting an Extreme Heat Warning from Sunday afternoon, Aug. 9, 2026, through Wednesday, Aug. 12, 2026, according to the National Weather Service in St. Louis.High temperatures are forecast in the mid-90s today. The warning comes as heat index values are expected to remain at levels that meet excessive heat criteria, the weather service said.The National Weather Service in St. Louis says an Exces...