DES MOINES, Iowa (AP) – The latest U.S. Drought Monitor map shows conditions have worsened in the Corn Belt states of Iowa and Nebraska.  The map shows extreme drought has spread further into the western half of Iowa and covers all but a small section of southeast Nebraska, where severe drought is occurring. A few counties in central Nebraska are still listed as being under exceptional drought conditions.  The drought map is a project shared by the University of Nebraska-Lincoln, the U.S. Department of Agriculture and the National Weather Service. The latest map is based on conditions as of 6 a.m. Tuesday, so it doesn’t reflect rainfall from storms that passed through parts of both states later Tuesday and on Wednesday.