The Dynamical Influences of Low-Level Shear and Lifting Condensation Level on Supercell Tornadoes

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Abstract This research seeks to incorporate a vorticity decomposition technique into a numerical model to determine how the sources of vertical vorticity and mechanisms for its intensification, particularly focused on understanding the link between environmental parameters and the outflow/updraft positioning, relate to the development and intensification of near-ground rotation. This study will also produce a climatological summary of radar data. Supporting observations will be developed to corroborate findings from the modeling study. Intellectual Merit This study provides a conduit for significantly advancing our understanding in vorticity dynamics and mass balances in supercell thunderstorm environments. This study will provide detailed knowledge of the spatiotemporal distribution of vorticity sources, sinks and fluxes within severe storms. The application of prior transformative research by Rotunno (1988) to determine a "balance" between inflow and outflow in the vicinity of the mesocyclone is potentially groundbreaking, by providing a framework for determining an ideal balance relationship for radial mass flux (inflow vs. outflow), especially at low levels. This work could also provide a significant contribution to tropical cyclone, boundary layer, and general turbulence dynamics. The evolution of upscale energy cascade into dominant coherent structure could be explained in better detail by the proposed vorticity tracking methods. Broader Impacts This research has the potential to further improve tornado forecasts and warning procedures, through improved lead-times for warnings and reduced false alarm rates. Moving beyond simple correlations between various environmental parameters to more a process-oriented conceptual model of supercell thunderstorm dynamics has broader impact across a full range of scientific fields of study. The investigators will use conference presentations and peer-reviewed publications as their primary means of disseminating results to the weather forecasting community. This study includes a plan to engage undergraduate students through an ongoing Research Experiences for Undergraduates (REU) program at Texas A&M University. The study also includes plans to disseminate educational materials through the UCAR Spark program. The Spark Program is the education and outreach program for the National Center for Atmospheric Research (NCAR) and its managing organization, the University Corporation for Atmospheric Research (UCAR). Spark is a service organization that assists NCAR and UCAR translate their research and operations activities into scientifically accurate, pedagogically effective, and broadly disseminated educational experiences and resources. In addition, Spark works to broaden the diversity within the STEM workforce.