Storm-environment interactions controlling the probability of supercell tornadogenesis

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The goal of this project is to improve our understanding of why some supercells (rotating thunderstorms) produce tornadoes and others that form in very similar atmospheric conditions do not. The specific chain of processes that result in tornado formation (vs. failure) are known to be highly sensitive to seemingly minor details within the environment and the storm itself. While our community has made substantial progress at forecasting tornadoes in recent decades, we have yet to explain why tornadoes so frequently fail to form within seemingly favorable atmospheric conditions. The specific aim of this research is to understand better these failure points in tornado formation. Without such progress, the ability to forecast and produce timely warnings for tornadoes (and avoid false alarms) is unlikely to further improve. The leading scientists for this project will involve students from diverse background and weather forecasters from the National Weather Service in this research. The expected outcome would improve our basic understanding of how tornadoes form and lead to improvements in public forecasts and warnings.The investigators seek to advance our fundamental scientific knowledge of supercells and tornado formation through hypothesis-driven research. The proposed work will directly compare the attributes of tornadic and nontornadic supercells with a hierarchy of computer modeling techniques, including large ensembles of simulations and incorporating novel techniques to emulate environments that vary in time. The proposed work will also quantify the roles of environmental (external to the storm) vs. within-storm processes in supercell tornado formation. Finally, the proposed work will explain the precursors (prior to storm formation) responsible for the generation of favorable environmental conditions for tornadoes (specifically, the atmospheric wind profile very near the ground).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.