Numerical Simulation Output for the Markowski (2024) Tornadogenesis Study

This dataset contains the model output created and analyzed by Markowski (2024) in his study of tornado formation in a high-resolution simulation of a supercell thunderstorm. A simulation produced for a prior study on tornado predictability (Markowski 2020) is reanalyzed for the purpose of examining the fine-scale details of tornadogenesis. It is found that the formation of a tornado-like vortex in the simulation differs from how such vortices have been understood to form in previous numerical simulations. The main difference between the present simulation and past ones is the inclusion of a turbulent boundary layer in the storm’s environment in the present case, whereas prior simulations have used a laminar boundary layer. The surface layer in the turbulent environment contains significant vertical vorticity (> 0.03 /s at z = 7.5 m) organized in the form of streaks aligned with the southerly ground-relative winds. The vertical vorticity streaks are associated with corrugations in the vertical plane in the predominantly horizontal, westward-pointing environmental vortex lines; the vortex-line corrugations are produced by the vertical drafts associated with coherent turbulent eddies aligned with the southerly ground-relative winds. The environmental vertical vorticity streaks serve as focal points for tornadogenesis, and may actually facilitate tornadogenesis, given how near-surface vertical vorticity in the environment can rapidly amplify when subjected to the strong, persistent convergence beneath a supercell updraft. In addition to the model output, the dataset also includes all code used to perform the analyses and create the figures shown in the above-referenced journal publication.