* WHAT...Heat index values up to 95 to 105.
* WHERE...Portions of central, east central, southeast, and west central Illinois.
* WHEN...Until 7 PM CDT this evening.
* IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
* ADDITIONAL DETAILS...As thunderstorms move in with the rains, temperatures and heat indices will drop quickly, ending the heat threat late this afternoon.