Thunderstorm Wind in Union County, Iowa

Time estimated by radar.

Multiple rounds of storms moved across the area on April 26th. The first round was fueled by broad thermal lift and passed across Iowa through the morning with a few of these storms producing small hail but all remained sub severe. The area dried out and cleared out behind this round, allowing for a few hours of destabilization. By afternoon the warm sector was sufficiently unstable between the warm front and a dryline. Robust convection developed along that dryline in the afternoon in western Nebraska, moving into Iowa in the early evening. With sufficient instability, the increasing low level jet, and SRH exceeding 300 m2/s2, large hail and tornadoes occurred with storms across western to central Iowa. In all, 28 tornadoes occurred in Iowa with 18 within the NWS Des Moines area.