Understanding the Internal Structure and Near-Storm Environments of Supercells via Innovative Analysis of Targeted Observation by Radars and UAS of Supercells (TORUS) Observations

The question of why some supercell thunderstorms develop tornadoes while others do not is an ongoing area of study in the severe weather research community. Prior research has suggested that certain near-storm environmental conditions may play a large role in determining whether a supercell will become tornadic. In 2019 and 2022, NSF and NOAA supported an observational campaign to make fine-scale measurements of the conditions around supercells. This award will apply advanced data analysis and modeling techniques to the observational data collected in that campaign to answer questions about the relationship between near-storm environmental conditions and tornadogenesis. The societal impact of this project will be found through the increased understanding of the conditions that form tornadoes and the dissemination of findings to the operational meteorological community. Three early-career researchers will be trained under this award, assuring the development of the next generation of scientists. This award is for analysis of data collected during the Targeted Observation by Radars and UAS of Supercells (TORUS) campaign that conducted field seasons in 2019 and 2022. The TORUS project sought to improve understanding of small-scale processes in supercells by elucidating the relationship of storm-generated boundaries and coherent structures within storm outflow to the generation/amplification of near-surface rotation. Under the TORUS umbrella, this award has the overarching goal of improving understanding of why some supercells produce tornadoes and others do not. The research team plans to synthesize TORUS observations via multi-Doppler wind syntheses, diabatic Lagrangian analyses, and ensemble data assimilation methods to address three main research foci: 1. Understanding streamwise vorticity currents (SVCs) and storm-internal boundaries and their relationship to amplification of near-ground rotation in supercells. 2. Understanding observed relationships between supercell updraft and inflow properties. 3. Understanding supercell inflow evolution and its relationship to storm properties. 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.