Verification of RUC analyses using VORTEX2 soundings for non-tornadic and tornadic supercell environments

In the past two decades, considerable progress has been made regarding our understanding of how lower tropospheric profiles of temperature, humidity, and winds favor non-tornadic versus tornadic supercells. These advancements have primarily been based on proximity soundings derived from the RUC model, due to insufficient coverage of observed upper-air radiosondes. However, NWP models inherently rely on parameterization schemes to account for process not represented on the grid-scale, and this can lead to errors in both the analyses and forecasts when compared to observed soundings (even at 0 and 1 hr). Issues in the planetary boundary layer are of particular interest in the present work because of the importance of boundary layer humidity and 0 – 1 km storm-relative helicity in the supercellular tornadogenesis process. In observed proximity soundings, previous studies have shown that storm-relative helicity in the lowest 500 m demonstrates the highest discrimination between non-tornadic and tornadic supercells. In fact, the low-level wind orientation and 0 - 500 storm-relative helicity were the most striking environmental difference between the VORTEX2 non-tornadic and tornadic supercells. In this study, the observed VORTEX2 near-inflow soundings will be compared to the corresponding RUC 00 hr analyses in an attempt to answer the question of whether our best-available gridded observation dataset can reproduce the seemingly subtle differences between the environments of non-tornadic and tornadic supercells surveyed during VORTEX2.