Comparison of Near- and Far-Field Supercell Inflow Environments Using Radiosonde Observations

A great deal of research focuses on how the mesoscale environment influences convective storms, but relatively little is known about how supercells modify the nearby environment. Soundings from three field experiments are used to investigate differences in the near and far inflow of supercell thunderstorms. Close-range soundings in the near inflow of supercells are compared to near-simultaneous soundings released farther away (but still within inflow). Several soundings from the second field phase of the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) supplement the Mesoscale Predictability Experiment (MPEX/MiniMPEX) dataset, resulting in 28 near–far inflow pairs from a wide variety of tornadic and nontornadic supercells. The focus of this study is on a comparison of a subset of 12 near–far inflow pairs taken near tornadic supercells and 16 near–far inflow pairs taken near nontornadic supercells. Similar values of 0–1-km storm-relative helicity (SRH01) are found in the far field of the tornadic and nontornadic supercells, possibly as a result of a difference in mean diurnal timing. However, SRH01 is found to increase substantially in the near field of the tornadic supercells, but not the nontornadic supercells. Differences in the thermodynamic environment include greater moisture above the ground in the far field of the tornadic supercells (despite similar near-ground moisture in both the tornadic and nontornadic subsets) and a subtle increase in static stability near the surface in the nontornadic near inflow.