Tornado in Polk County, Iowa

This tornado remained in rural cropland. No damage indicators were impacted, hence the EFU rating.

Scattered convection occurred throughout the day across the area as a weak cold front dropped slowly south across the area. By afternoon the front had largely stalled near the I-80 corridor and more vigorous convection developed along the front, fed by high instability exceeding 3000 J/kg and steep mid level lapse rates of 7 to 8 C/km. Storms first began near Newton and then back built towards the west along the boundary through the evening. Storms produced large hail and stretching resulted in a huge number of funnel clouds, including pictures with a least visible at the same time. Later in the evening a wave across Nebraska moved into Iowa, sweeping east along the instability gradient that the earlier evening convection developed on. A few damaging wind gusts occurred with this line of storms, however it remained sub severe most of the night.