The National Weather Service has issued an extreme heat warning for all of Madison County, including Edwardsville, Glen Carbon, and Alton, through 9 p.m. July 27.
The warning is also in place for St. Clair and Monroe counties in Illinois; St. Charles, St. Louis, and Jefferson counties in Missouri; and the city of St. Louis.
The warning says the region will see dangerously hot conditions, with heat index values as high as 121 degrees…