June 6, 2011: Hail in Columbia, Dodge and Sauk Counties

Low level warm air advection and moisture transport produced increasing instability over the region as it pushed a surface warm front toward Wisconsin during the early morning hours of June 6th. A cluster of strong to severe elevated thunderstorms formed on the leading edge of the strengthening low-level jet as it veered south-southwest, focusing on southern Wisconsin during the early daylight hours. Moderate elevated instability...steepening mid-level lapse rates and increasing effective bulk shear up to 50 knots supported the development of severe thunderstorms with large hail that affected mainly the northern half of the Milwaukee/Sullivan County Warning Area.