Environmental Controls on Tornadogenesis

Supercell thunderstorms are among the most deadly storms due to their enhanced capability to produce high winds, tornadoes, rain, and hail. While supercells are relatively well forecast, determining which supercells are likely to produce tornadoes is still difficult to forecast in advance. This work utilizes the open-source Regional Atmospheric Modeling System (RAMS) to perform a series of idealized supercell simulations with homogenous initial conditions representing both tornadic and non-tornadic supercells. These simulations were run at very fine grid spacing, thereby allowing for the resolution of a near-surface tornado-like vortex. Two initial soundings were generated that represent non-tornadic but supercell producing and tornadic environments. The homogenous initial environmental conditions were then perturbed independently and synergistically between the two soundings to produce a factor separation analysis. This allowed for the determination of which factors lead to an increased chance of tornadogenesis. Finally, the characteristics of both the tornadic and non-tornadic supercells were examined to determine the differences in storm structure and the mechanisms that lead to the development of the mesocyclone in all cases.