Data from the National Lightning Detection Network (NLDN), Lightning Mapping Array (LMA), dual-polarization radars and other meteorological observations will be used to investigate the potential direct role of lightning discharges in tornadogenesis. The LMA, NLDN and other lightning networks will be used to document the total lightning flash counts (i.e. in-cloud (IC) and cloud-to-ground (CG)), three-dimensional flash structure and other lightning properties in and around the tornado and the larger supercell. LMA source data in the vicinity of the tornado will also be inspected for the coherent presence of so-called singletons (or isolated VHF points) and other low source number discharge events that fail to satisfy temporal and spatial clustering or minimum source number criteria typically used to associate VHF sources into flashes. Both Doppler and dual-polarimetric radar signatures, including the tornado vortex signature (TVS) and the tornado debris signature (TDS), in conjunction with NOAA's SPC Severe Storm Reports and detailed damage surveys will be used to identify the location of the tornadic circulations. Dual-polarization and dual-Doppler radar techniques and meteorological observations will also be employed to understand the kinematic, microphysical and thermodynamic structure of these storms and their environment in relation to tornadogenesis and the electrical structure.
Initially, two tornadic supercell case studies, which occurred in northern Alabama on 27 April 2011 and 2 March 2012, will be analyzed. Each supercell will be examined in depth to determine if frequent lightning flashes or other discharge events occur in and around the vortex core. Also, understanding of the potential role of cloud thermodynamic, microphysical and dynamical forces present in the storm environment prior to tornadogenesis will be derived from the dual-Doppler radar and meteorological analysis in each case.