* WHAT...For the first Heat Advisory, heat index values up to 105. For the second Heat Advisory, heat index values up to 107 expected. * WHERE...Portions of East Arkansas, North Mississippi, Southeast Missouri, and West Tennessee. * WHEN...For the first Heat Advisory, until 8 PM CDT this evening. For the second Heat Advisory, from noon to 8 PM CDT Tuesday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.