September 17, 2012: Hail in Walworth County

Forcing for ascent associated with a short-wave trough crossing southern Wisconsin during the afternoon of September 17th enhanced lift along a surface cold front passing through the region. Upper-level divergence associated with the right entrance region of an upper-level jet coincided with the passage of the cold front over Southeast Wisconsin...enhancing thunderstorms that had developed along the front. A few of the storms became severe, producing damaging winds and large hail.