Evolution of Single- and Dual-Polarization Radar Signatures Associated with QLCS Mesovortices

The purpose of this study is to identify and analyze potential single- and dual-polarization radar precursor signatures associated with tornadic and nontornadic quasi-linear convective system (QLCS) mesovortices. QLCS tornadoes present many forecasting challenges based on their rapid development, transience, and dynamic environment. QLCS tornadoes can form in between radar volume scans so it is imperative for forecasters to locate potential key radar signatures to issue tornado warnings in advance of tornadogenesis. Having the ability to detect early radar signatures of QLCS tornado development can potentially increase tornado warning lead time to the public and help those in danger better prepare for the risks tornadoes pose. Radar analysis was conducted on 18 tornadic and 5 nontornadic mesovortices using the Warning Decision Support System-Integrated Information (WDSS-II) software. Single-polarization products analyzed included spectrum width, reflectivity, and velocity; dual-polarization products analyzed included correlation coefficient, differential reflectivity (Z_DR), and specific differential phase (K_DP). The analysis showed that the most beneficial radar precursor signatures for anticipating potential QLCS tornado development may be Z_DRcolumns, enhanced areas of low-level K_DParound developing mesovortices, updraft/downdraft convergence zones along the leading edges of QLCSs, as well as low-level concentrated areas of enhanced spectrum width.