Variability of "environmental" wind profiles and the role of boundaries during VORTEX

The variability of storm-relative helicity during VORTEX will be documented. It will be shown that roughly two-thirds of significant tornadoes during VORTEX occurred near boundaries not associated with the forward- or rear-flank gust fronts of the tornadic storms. Thus, tornadogenesis may require local augmentation of low-level horizontal vorticity or storm-relative helicity. Regions of enhanced vorticity, while often not detectable, can often be inferred from "conventional" data.