An analysis of lightning activity in response to microphysical processes in Southeast U.S. Storms

The Verification of the Origins of Rotation in Tornadoes EXperiment-Southeast (VORTEX-SE) field campaign was first held March-April 2016 and 2017 with the primary goal of understanding how attributes of environments in the southeastern U.S. influence thunderstorm formation, intensity, and structure leading to the development of tornados. Lightning is a fundamental component of these environments. In order to better understand the relationship between the structure of multi-cell or quasi-linear convective systems (QLCSs) and lightning, it is necessary to understand the origin of fluctuations in lightning activity. Specifically, we seek to understand how lightning metrics correspond to storm microphysics and kinematics. Lightning is indicative of and related to kinematic changes within thunderstorms, with significant changes in the mixed phase updraft leading to rapid increases in lightning. Larger charge reservoirs can also be created by advection of hydrometerors. Thunderstorm electrification is a product of the microphysical environment, as such lightning is intimately related to microphysical conditions within the thundercloud. Microphysical conditions are also deeply connected to thunderstorm kinematics via precipitation mode, up/downdraft metrics, and cold pool evolution. Centering this project on the lightning signal in QLCSs, we relate lightning observables, including flash rate, size, and extent, to mixed phase draft variability. Specifically, we examine QLCSs as case studies, building on current storm evaluations, and identify consistent characteristics across the four case days. This project utilizes ground-based lightning data from the lightning mapping array (LMA), with surface StickNet measurements to complement radar and hydrometeor ID datasets. We utilize radar data to probe the microphysical structure, including graupel volume, ice volume, Zdr and Kdp columns. At the cellular scale, an analysis of the spatial and temporal relationships among lightning activity, storm microphysics, cold pool evolution, and draft metrics will be presented.