56 Localized vorticity enhancement through superhelical coherent structure in the Goshen tornadic supercell

Tuesday, 4 November 2014
Capitol Ballroom AB (Madison Concourse Hotel)
Marcus L. Büker, Western Illinois University, Macomb, IL; and L. Odell, G. J. Tripoli, and S. T. Trevorrow

We present observational and numerical analyses of coherent structure within a tornadic supercell during the time leading up to tornadogenesis. The main diagnostics focus on the gradients of helicity and superhelicity, quantities shown to be strongly related to local maxima in vorticity tendency. Mobile Doppler radar retrievals from the well-known Goshen, Wyoming storm are used for the observational portion of the study, while high resolution numerical simulations of the storm are analyzed in a similar fashion. The results show promise for detecting and tracking coherent dynamical features known to be related to tornadogenesis, as well as detecting signals of imminent tornadogenesis at an earlier stage than conventional vorticity tendency analysis. Furthermore, these methods may provide physical insight into vortex-vortex interactions and vortex modes in the vicinity of the mesocyclone circulation.
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