EF1 Tornado — Shelby, Iowa

2024-05-06 · near Shelby, Shelby, Iowa

Event narrative

This is a continuation of the EF-1 tornado that started in Pottawattamie County. This tornado crosses into far southwest Shelby County just east of the intersection of Elmwood Road and 100th Street. Several tree trunks were snapped along Elmwood Road as the tornado continued to the northeast. This tornado dissipated about a quarter of a mile into Shelby County. Peak wind speeds for this final segment of the tornado track were estimated at 88 mph. Peak tornado width was measured at 100 yards, with an average width in this segment of the track estimated at 50 yards.

Wider weather episode

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.

View location on OpenStreetMap → (41.5060, -95.4790)

Source: NOAA Storm Events Database, event_id 1180507. Narrative written by the NWS forecast office that issued the report.