There was a nice example of small vortices forming along an outflow boundary with a line of convection in the FSD county warning area around 1545Z  on 16 April. These small vortices are sometimes  associated with storm damage from  non-supercell tornadoes or “gustnadoes”. The TORP identified one of these circulations with rapid increases in both AzShear and Spectrum Width Maximum trend.

Posted by Rigel