The Storm Prediction Center has issued a Severe Thunderstorm watch effective until 10pm this evening for the following counties, Appanoose, Black Hawk, Bremer, Butler, Clarke, Davis, Decatur, Grundy, Jasper, Lucas, Mahaska, Marion, Marshall, Monroe, Poweshiek, Tama, Wapello, Warren, Wayne, Benton, Buchanan, Cedar, Clinton, Delaware, Des Moines, Dubuque, Henry, Iowa, Jackson, Jefferson, Johnson, Jones, Keokuk, Linn, Louisa, Muscatine, Scott, Van Buren, Washington, Jo Daviess IL, Mercer IL, Rock Island IL, Allamakee, Winneshiek, Clayton, Fayette, Chickasaw, Howard, Crawford WI and Grant WI. Thunderstorms have developed over the central counties of the state this afternoon. The main threats from these storms will be from damaging winds and large hail. Heavy rain is not a threat at this time mainly due to the quick motion of the storms but there will be some substantial amounts to help ease the dry ground.