EF1 tornado in St. Joseph County, Indiana

The tornado began west of the intersection of Riley Road and Dogwood Road in southeast St. Joseph County. It then tracked along and south of Riley Road. Widespread tree and structural damage occurred through this path. Grain bins were toppled and farm outbuildings sustained damage. The tornado tracked through several cornfields that resulted in significant crop damage. The tornado lifted east of Beech Road. Maximum winds were estimated at 110 mph.

Convectively enhanced vorticity max lead to initiation of storms overnight Sunday across southern South Dakota. These initial storms grew upscale given concurrent downstream destabilization through northeast Nebraska and northwest Iowa. Widespread 80-100 mph winds developed through central/eastern Iowa as this derecho matured. Northern bookend and advection wing forcing led to some supercell structures across northern Illinois/southwest Wisconsin. Northern bookend turned northeast as it moved across Lake Michigan and tracked into western Michigan. As this occurred, attendant post convective wake low weakened as it crossed the lake. Thus the local area did not experience the 80 to 100 mph winds that N IL/E IA experienced. However the resultant slowing and breakup of the line as it moved across northwest Indiana/SW Michigan, yielded a LEWP and subsequent multiple small scale circulations developing along the line. These meso-vortices were associated with pockets of enhanced wind damage and brief tornado occurrences.