HEAT ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT CDT /1 AM EDT/ TONIGHT... * WHAT...Peak afternoon heat indices of 100 to 105 degrees expected. * WHERE...Portions of central, east central, north central, and northeast Illinois and northwest Indiana. * WHEN...Until midnight CDT /1 AM EDT/ tonight. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. PRECAUTIONARY/PREPAREDNESS ACTIONS... Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.