The Storm Prediciton Center has issued a Severe Thunderstorm Watch which is in effect until 10pm for the following counties, Benton, Cedar, Clinton, Des Moines, Dubuque, Henry, Iowa, Jackson, Jefferson, Johnson, Jones, Keokuk, Lee, Linn, Louisa, Muscatine, Scott, Van Buren and Washington. Thunderstorms are currently developing in the southwestern parts of the state and will move into the watch area later this afternoon and this evening. Large Hail and damaging straight line winds similiar to this morning will be the main threats.