* WHAT...Heat index values up to around 105. * WHERE...Portions of east central and northeast Kansas and central, north central, northeast, northwest, and west central Missouri. * WHEN...Until 8 PM CDT Friday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS...While heat index values may not reach 105 each day, the combination of the longevity of the heat and little or limited relief during overnight periods have prompted the multi-day Heat Advisory.