Hail in Woodbury County, Iowa

A trough lifted through the western High Plains as a weak convergence boundary drifted eastward into southeast South Dakota during the late afternoon. Near the boundary, a diurnally destabilized air mass focused convective development in a fairly weak shear environment across the lower James River Valley. Thunderstorms largely produced large hail up to ping-pong ball size during periods of stronger updrafts within the storm clusters. Shear concentrated in lower levels and storm interactions combined to produce several brief tornadoes in southeast South Dakota. Storms weakened as they headed into northwest Iowa during the evening but still produced some hail up to ping-pong ball size and strong thunderstorm winds.