June 19, 2009: Straight-line wind in Walworth County

The final in a series of upper level disturbances propagated northeastward across southern Wisconsin during the afternoon and evening of June 19th. This impulse, combined with strong upper level jet dynamics and a very moist, unstable atmosphere, allowed for storms to redevelop across southern Wisconsin. Bulk shear values of 50-60 kts, MLCAPE values near 2500 J/kg, and PW values near 1.8 allowed for a series of short thunderstorm lines to move through southern Wisconsin. The result was wind damage, a tornado in Kenosha County, and widespread flash flooding. Due to the heavy rainfall from earlier storms, some locations received 3 to almost 7 inches of rain in less than 24 hours. Flash flooding occured in Kenosha, Walworth, Waukesha, Milwaukee, and Racine counties.