Collaborative Research: Processes that Regulate Vertical Accelerations in Supercell Updrafts

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The especially intense updrafts in supercell thunderstorms facilitate the production of large hail, tornadoes, extreme rainfall rates, and prolific lightning. As a result of their great impacts on society, considerable research efforts are warranted to better understand and predict the environmental factors that contribute to the vertical accelerations that give way to supercells' impressive updrafts. This collaborative research effort will utilize numerous, innovative high-resolution numerical modeling experiments coupled with observational datasets in order to understand the forcing for supercell updrafts at various heights over a range of realistic near-storm environments. Thus, this work has tangible broader impacts to society through its potential to improve understanding and forecasting of supercell thunderstorms and their related hazards as well as through training of a new generation of scientists. Motivated by a current lack of comprehensive understanding in these areas, this research will investigate the following scientific questions: (1) How do low-level stability, low-level shear, and low-level storm-relative flow conspire to determine a storm's effective inflow layer? (2) How do concurrent changes in low-level stability and shear, as occurs during the evening transition, influence the ratio of air ingested from different layers and the vertical profiles of buoyant and dynamic pressure accelerations in the lower portion of a supercell updraft? (3) How might the connection between storm-relative flow and updraft width influence an updraft's profile of buoyant and dynamic vertical accelerations? These questions will be answered using numerical simulations with a range of realism from highly idealized to real-data simulations of observed storms, wherein quantities such as the effective inflow layer, updraft forcing, and entrainment will be compared and verified via dual-Doppler radar observations when available.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.