Extreme Heat Warning

* WHAT...For the Extreme Heat Warning, dangerously hot conditions with heat index values up to 111. For the Heat Advisory, heat index values up to 102 expected.

* WHERE...In Illinois, Madison IL County. In Missouri, Saint Charles MO, Saint Louis City MO, and Saint Louis MO Counties.

* WHEN...For the Extreme Heat Warning, until 9 PM CDT this evening. For the Heat Advisory, from 9 PM this evening to 7 PM CDT Tuesday.

* IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. Hot temperatures and high humidity may cause heat illnesses.