EF2 tornado in Posey County, Indiana

An EF-2 tornado struck western Posey County, IN, during the early morning hours of April 2nd. This tornado began in far eastern White County, IL, before proceeding to cross the Wabash River into Posey County. The tornado crossed through Harmonie State Park causing significant tree damage. The tornado tracked to the south-southeast, crossing IN-69 near Lynn with several pine trees snapped at the base. Additional tree damage occurred on Harmony Springfield Rd and Springfield Rd, the latter of which also had an outbuilding collapse. The tornado crossed Oliver Rd and Wade Rd, destroying multiple outbuildings and a grain bin while damaging a roof on Oliver Rd. The tornado track shifts northeastward, eventually merging with another tornado west-southwest of the town of Blairsville. In total, hundreds of trees were uprooted or snapped, several outbuildings/sheds were damaged or destroyed, and minor to moderate roof damage occurred to several homes. Estimated peak wind speeds for the tornado as a whole, and in the Posey County segment, are 115 mph.

Early morning, the surface low was located just north of St. Louis, Missouri, lifting to the NNE as it rapidly deepened. For Southwest Indiana, early morning effective bulk shear was 65-70 kts, with a very high 25-30 kts of 0-1 km shear, while SRHs were around 150-200 m2/s2. MLCAPE was 1000 J/kg, and mid-level lapse rates were 7 C/km. A 70-90 kt mid-level jet was west of the Quad State. A strong capping inversion suppressed storm activity in the evening, but the strong lift and upper level diffluence won out early morning. Two lines of storms developed after midnight in Southeast Missouri. The first just missed to the north of Gibson County. The latter was a very potent thunderstorm line racing eastward early morning April 2nd. This line continued throughout the day all the way to West Virginia, being designated a derecho. For Southwest Indiana, widespread wind damage occurred with this line, and sections of the line that took a north-south orientation had a much more favorable line-normal component of shear promoting QLCS tornado development. This was the case for Posey, Vanderburgh, and Warrick Counties. Seven tornadoes originated in Southwest Indiana: 2 (both EF-2) in Posey County, 3 in Vanderburgh County (1 EF-2 and 2 EF-1), and 2 in Warrick County (both EF-1). Including county crossovers, there were 4 tornadoes in Posey County, 4 in Vanderburgh County, and 6 in Warrick County. Four tornadoes crossed from Vanderburgh into Warrick County at approximately the same time. There were also 3 microbursts/macrobursts south of the tornado tracks: a microburst in Posey County, a macroburst that progressed from Parkers Settlement in Posey County to Melody Hill in Vanderburgh County, and a microburst south of Boonville in Warrick County. A total of 19 tornadoes were found during this event, the highest single day total for the NWS Paducah forecast area since Halloween 2003 (also 19). Vanderburgh County EMA tallied up at least 42 structures damaged (including 5 with roof damage, 7 houses damaged or destroyed, 7 hours with trees on them, 15 barns or storage structures damaged or destroyed, a gas station overhang blown over, and a radio tower blown over). Additionally, 4 semis or semi-trailers and 4 cars were blown over. Numerous metal power poles were blown over and bent in half along US-41.