EF1 tornado in Wapello County, Iowa

Tornado formed initially as a broad circulation east of Highland Center. First damage was to a farm site where a chicken barn was destroyed and two power poles were snapped. As the tornado traveled quickly to the northeast and struck utility poles producing a considerable lean. The tornado then continued into Keokuk county.

A strong upper low moved into the central United States. Surface low pressure was located over northwest Kansas into southwest Nebraska during the late afternoon. A warm front extended from the low across northern Missouri into southern Illinois. A strong push of moisture took place south of the front with dewpoints rising into the upper 50s to low 60s. Precipitable water values increased to around 1.3 inches. The freezing level was relatively low, around 11,000 feet. The atmosphere was strongly sheared with 50 to 60 kts of shear available. By the afternoon, the atmosphere became unstable with 1000 to 2000 J.kg of CAPE available. Downdraft CAPE was quite high in the 700 to 1000 J/kg. CAPE in the -10 to -30 C layer of the atmosphere was around 200 J/kg. A strong line of thunderstorms formed on the east edge of the dry slot as it pushed into Iowa. Thunderstorms remained below severe levels through the morning, however, they intensified as the moved into south central and southeast Iowa. One tornado touched down in Wapello County before racing northward into Keokuk County. There were numerous reports of high winds as the line progressed east with winds of 60 to 70 MPH. Numerous trees were blown down by the high winds. The roof was taken off of a family medical center in northeast Oskaloosa in Mahaska County. Major structural damage was reported on a farmstead west of Ottumwa in Wapello County with outbuildings damaged and roof damage to the porch of the farmstead. Windows were blown out of cars and roofs were blown from buildings on a farmstead east of Cincinnati in Appanoose County. Ten people were injured, some requiring hospitalization, on the south side of Ottumwa. At least four of the ten were injured when thunderstorms winds lifted debris at an auction on the south side of the city. One injury was reported in Appanoose County when a woman was struck by debris lifted by strong winds. Lightning struck a car near Osceola in Clarke County. It struck the trunk of the car and set the trunk on fire.