EF1 tornado in Mills County, Iowa

A tornado developed and snapped trees at a home on Lucas Road, moving quickly to the northeast where it cut a 30 yard wide swath of snapped trees and branches. Additional sporadic tree damage was noted near Kane Avenue. A farm was badly damaged along Jagger Road, with one large shed completely destroyed and two large grain bins destroyed with debris deposited a half mile downstream. The tornado then crossed Highway 34 a quarter-mile west of 270th Street damaging a power pole. Damage continued northeast through open fields crossing the Burlington Northern Santa Fe line where large tree branches were snapped. The tornado continued northeast damaging two farmsteads along Hershey Avenue where several outbuildings sustained high-end EF1 damage. Many trees were snapped at both farmsteads. Peak estimated winds from this tornado were 100 miles per hour. This tornado achieved a maximum width of 250 yards, with an average width estimated at 150 yards.

Upper air analysis depicted a negatively tilted trough over the western CONUS, with its axis extending from the central Rocky Mountains northwest into the Pacific Northwest. At the surface, a low-pressure center was deepening over the northern High Plains along with a secondary surface low in western Nebraska. Extending south out of these pressure centers was a Pacific cold front. At 21 UTC, a warm front was noted to extend southeast from southwest Nebraska into northeast Oklahoma. As the evening progressed, strong warm air advection ahead of the mature low-pressure pushed the warm front north into eastern Nebraska by 00 UTC.

Along this warm front and ahead of the Pacific cold front, several lines of strong to severe thunderstorms moved through eastern Nebraska and western Iowa. The first line of strong storms moved through central and northeast Nebraska after 4:30 PM CDT. No severe reports were associated with these storms in the OAX CWA. Another intensifying segment of the same line moved into southeast Nebraska by 7:30 PM CDT, this time south of the northward advancing warm front. These storms tracked northeast through southeast Nebraska and southwest Iowa, producing numerous severe wind gusts across the area and multiple spin-up tornadoes. The vast majority of wind gusts recorded with these storms ranged from 55 to 70 miles per hour. The strongest wind gust was measured at 71 miles per hour in Richardson County. 2 EF-0 tornadoes were confirmed in southeast Nebraska, both in Gage County. There were also an additional 3 tornadoes confirmed in southwest Iowa, all EF-1 tornadoes.