Radar-detected Mesocyclone Tilt in Tornadic and Nontornadic Supercells

While supercell thunderstorms are the storms with the greatest potential of producing tornadoes, the majority of supercells do not produce tornadoes. This study builds a climatology of radar data to distinguish between tornadic and nontornadic supercells that will complement an idealized modeling study. Level- II Weather Surveillance Radar-1988 Doppler data were collected for isolated supercells in the contiguous United States from 2009 to 2014. This period was selected to overlap with the additional research data collected during the Second Verification on the Origins of Rotation in Tornadoes Experiment.

From this initial climatology, low-level (LL) and mid-level (ML) azimuthal wind shear maxima are located (representing the LL and ML mesocyclones), and the horizontal distance between each maximum is calculated during the evolution of each supercell. It is expected that as the horizontal distance between the LL and ML mesocyclones increases, the likelihood and intensity of a tornado both decrease. Statistical analysis of the climatology and results from individual cases, including the dependence of separation between LL and ML mesocyclones on the environmental vertical wind shear from proximity soundings, will be presented.