Thunderstorm Wind in Dubois County, Indiana

A large tree was blown down, blocking Indiana State Road 164 near Celestine.

On May 18th into May 19th, the Ohio Valley was in the middle of a southwest mid- and upper-level flow regime between troughing over the central CONUS and southeast US ridging. Smaller scale perturbations within the broader flow pattern would support a couple waves of showers and thunderstorms, with isolated strong to severe storms occurring across north central Kentucky and southern Indiana during the afternoon and evening hours both days. On May 18th, storms which initially developed as scattered cells over southern Illinois merged into a line across southern Indiana. This line of storms had a modest amount of instability and vertical wind shear to support it, with temperatures in the upper 80s and dewpoint temperatures in the upper 60s supporting 1500-2000 J/kg of mixed-layer CAPE. Scattered wind damage was observed across southern Indiana, with the greatest concentration of damage occurring in Dubois and Washington County, where several trees were blown down. Additional rounds of showers and thunderstorms later in the evening would also lead to a few occurrences of flash flooding, especially along tributaries of the Blue River in Washington County.