Vertical Growth of a Vortex in a Supercell Using a Three-Dimensional Inertial Frequency

Recent observational studies of supercells suggest that vertical vorticity increases rapidly over a large vertical depth of the lower troposphere during tornadogenesis. A pre-tornadic vortex (PTV) is often noted on doppler radar as a radial velocity couplet prior to the development of a tornado. Although vertical vorticity, pressure minimum and horizontal wind techniques have taught us a lot about the development of intense vortices in supercells, there is still ambiguity on the origin of the tornado. To investigate the iniation location of a tornadic vortex in the vertical column and the subsequent vertical growth, a three-dimensional inertial frequency is defined and used with multiple doppler radar observations of supercells. The metric isolates the part of the full flow that is in balance with pressure gradient forcing, neglecting deformational and divergent parts of the flow characteristic of a turbulent supercell environment. The aim of this work is to draw attention to using such a metric together with high-resolution, three-dimensional radar retrievals of tornadic supercells that will afford a more accurate look into where a tornado first develops in these storms. Results of using the metric with such retrivals will be presented at the symposium.