A Study of Inferred Charge Advection in Mesoscale Convective Systems on the South Plains Utilizing the West Texas Lightning Mapping Array

The study of lightning in thunderstorms has had a long history of research leading to theories on charge generation, charge structure and flashes within storms. Systems such as the National Lightning Detection Network (NLDN) and the Lightning Mapping Array (LMA) have been used to develop, test, and refine each of these theories. One outstanding question concerns the distribution of charge and lightning in mesoscale convective systems (MCS). Much can be inferred about the convective line region of the MCS from what we know of lightning in thunderstorms, but the transition zone and the trailing stratiform region are still in need of further exploration. 

Previous research hypothesized that charge was advected from the tops of the convective cloud rearward into the trailing stratiform region. These studies, however, only focused on the fully formed MCS. Utilizing data from the West Texas LMA and the Lubbock, TX WSR-88D, we studied two MCSs as they evolved over the Texas South Plains. Individual flashes were logged and analyzed specifically looking for an increase in flash size of rearward flashes with time, an increase in the relative number of rearward flashes versus anvil flashes and a greater descent in altitude of rearward flashes with time. These elements, collectively, would show the development of the process of rearward advection of charged hydrometeors, a process that would be evidenced by flashes traveling through such hydrometeors. For comparison, two fully developed MCSs were also analyzed as they crossed the South Plains.