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Using Observations from Torus to Better Understand and Simulate the Evolution of Two Proximate Supercells on 8 June 2019
This study uses observations from the TORUS project collected in and around two supercells on 8 June 2019 to answer two related research questions. Firstly, why were the two supercells TORUS observed on 8 June so different in structure and hazard production, with the first storm being weak and nontornadic and the second supercell being stronger and cyclically tornadic? Secondly, how does assimilating different subsets of TORUS data into a storm-scale ensemble improve model forecasts of the evolution of convection on 8 June? The first question is explored with a detailed case study of the 8 June storms and their environments using mobile mesonet, UAS, and mobile sounding observations from TORUS as well as dual-Doppler analyses from the tail Doppler radar onboard the NOAA P3 aircraft. The second question is explored by using a series of data denial experiments to examine the impact of assimilating TORUS data from near the surface, within the PBL, and within the free atmosphere on storm-scale ensemble analyses and forecasts of the 8 June storms. Results from the first investigation indicate that the second storm’s greater intensity and tornado production were likely influenced by the rapid evolution of the near-storm environment to be more favorable for tornado production after the first supercell’s demise, by its interaction with a rapidly-developing new updraft on its rear flank, and by the simultaneous impact of a strong rear-flank internal surge wrapping around the western side of the storm during this interaction. Less confidence is placed in the potential impacts of two mesoscale boundaries encountered by the second supercell and differences in deep convection initiation on the differences between the two supercells. Results from the second experiment indicate that assimilating all of the TORUS observations together improves the ensemble forecasts much more often than it makes them worse; however, no one subset of the TORUS data consistently has the greatest positive impact.
Wilson, Matthew B, "Using Observations from Torus to Better Understand and Simulate the Evolution of Two Proximate Supercells on 8 June 2019" (2023). ETD collection for University of Nebraska - Lincoln. AAI30487502.