EF2 tornado in Posey County, Indiana

An EF-2 occurred in Central Posey County, IN, early morning on April 2nd. The path started just east of IN-69, resulting in tree and powerline damage as it moved southeastward towards Harmony Township Rd. Large portions of a roof were blown off a home on Harmony Township Rd, while a roof and several walls were blown off of a barn on Williams Rd. The tornado continued to track southeastward, eventually merging with another tornado west-southwest of Blairsville. North of Parkers Settlement, the tornado destroyed a barn on IN-66 and threw a garage roof south and east at Rexing Rd. The tornado lifted just north of Parkers Settlement, after which straight-line wind damage continued into Vanderburgh County on the north side of Evansville. In total, hundreds of trees were snapped or uprooted, dozens of outbuildings were damaged or destroyed, and minor to moderate damage occurred to several homes. Estimated peak winds with this tornado were 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.