Multiple-Doppler radar observations of the structure and evolution of vortices in a convective boundary layer

High-resolution (100 m and 90 s in space and time, respectively) wind syntheses are presented in order to document the morphology and evolution of boundary layer vorticity extrema observed during the IHOP deployment on 12 June 2002. The most prominent vorticity maxima, which attained values of 0.01 /s, tended to be located along the outflow boundary and within the warm sector to its south. The magnitudes of the vorticity extrema generally decreased with height from their largest values near the surface, although all of the significant vorticity extrema spanned the depth of the boundary layer. Individual patches of vorticity could be tracked for periods longer than an hour, during which vorticity would amplify and decay depending on the proximity to boundary layer updrafts and downdrafts. Interesting vortex interactions are documented, in addition to some observations of what appears to be the vortex valve effect, in which some vortices instigate their own demise by way of the development of an adverse vertical pressure gradient which eventually weakens the parent updraft and associated convergence. Contributions to vorticity tendency also are examined, from both Eulerian and Lagrangian perspectives.