* WHAT...Dangerously hot and humid conditions with multiple days of heat index values of 105 to 110 expected, along with nighttime lows not dropping below 75 degrees.
* WHERE...Portions of northwest and west central Illinois, east central and southeast Iowa, and northeast Missouri.
* WHEN...From 1 PM this afternoon to 9 PM CDT Tuesday.
* IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.