Evaluating Quasi-Linear Convective System Mesovortices Using Dual-Polarization Radar Data

Issuing convective warnings on quasi-linear convective systems (QLCSs) is a challenge for National Weather Service operations, as they develop quickly and are small-scale phenomena. To guide forecasters, the three ingredients method and QLCS mesovortex warning system were developed. However, this system doesn’t yet incorporate dual-polarization radar data. Therefore, this study compares radar signatures already within the mesovortex warning system to the evolution of specific differential phase (KDP) to determine if KDP offers any predictive ability (lead time) to mesovortex development and damage potential. To accomplish this study, we compared low-level KDP core, midlevel KDP core, and KDP drop evolution relative to mesovortex formation. We chose two QLCS events, 19 May 2022 in Saint Louis and 20 February 2017 in San Antonio, and examined the KDP signatures mentioned above for damaging vs non-damaging mesovortices and tornadic vs non-tornadic mesovortices. In general, KDP drops frequently precede mesovortex development and are slightly more frequent for mesovortices that produce damage. Midlevel KDP cores have a higher magnitude for tornadic and damaging mesovortices prior to mesovortex genesis, therefore potentially offering prognostic ability. Furthermore, low-level KDP cores have a higher magnitude for tornadic and damaging mesovortices during mesovortex life, therefore potentially offering diagnostic ability. These findings support the idea that KDP can be used by forecasters to build confidence in whether a given mesovortex might produce damage or not.