The Storm Prediction Center has issued a Severe Thunderstorm Watch that is in effect until 11pm for the following counties in Iowa, Fremont, Mills, Montgomery, Page, Pottawattamie, Adair, Adams, Audubon, Black Hawk, Boone, Bremer, Butler, Calhoun, Carroll, Cass, Cerro Gordo, Dallas, Franklin, Greene, Grundy, Guthrie, Hamilton, Hancock, Hardin, Humboldt, Madison, Marshall, Polk, Story, Webster, Worth, Wright, Allamakee, Chickasaw, Clayton, Fayette, Floyd, Howard, Mitchell and Winneshiek. Thunderstorms are developing along the cold front in North Central Iowa northeastward into SE Minnesota and western Wisconsin. Large Hail and damaging winds will be the main threats.