Vortex-vortex interactions and superhelicity in tornadic development and evolution

We present new diagnostic methods for localized, barotropic vorticity evolution in tornadic supercell environments. These methods focus on identifying local maxima in vorticity tendency, and how these features relate to a quantity known as superhelicity, which is present whenever gradients in horizontal vorticity (such as those associated with downdraft and updraft pulses) are orthogonal to a given background vorticity (such as in the vicinity of a mesocyclone). Using mobile Doppler radar retrievals from three well-known cases (Goshen, WY - 2009; Argonia, KS - 2001; and Orleans, NE - 2004) featuring tornadic supercells, these diagnostic methods show promise for tracking coherent dynamical features related to surface vortex intensification, as well as detecting signals of imminent tornadogenesis sooner than traditional vorticity tendency diagnostics. Furthermore, these methods may provide physical insight into vortex interactions and modes in the vicinity of the mesocyclone and flanking downdrafts. We also illustrate these relationships through numerical simulations of idealized vortex interactions.