Thunderstorm Wind in Cass County, Iowa

Strong wind gusts reported in Atlantic, with medium to large sized tree branches down blocking multiple roads. Pea-sized hail was observed at times, with heavy rain causing near zero visibility.

A stationary boundary was draped across northern Iowa on the morning of June 16th in an environment with very low shear and over 1500 J/kg MLCAPE. This allowed for isolated thunderstorms development through late morning, including one quarter sized hail report in northern Iowa. By afternoon a shortwave dropped out of South Dakota and across Iowa. By then MLCAPE had increased to 2500-3000 J/kg with the shortwave bringing 30-35 kts of 0-6 km shear. This allowed for better storm organization, resulting in a bowing segment with gusts up to 60 mph reported along with tree damage.