Lightning and polarimetric signatures of electrified winter storms in central Oklahoma

This study examines four winter storms and associated lightning activity in central Oklahoma between 2005 and 2010. These four events produced significant ice and snow totals as well as blizzard conditions across the state. Total VHF lightning data from the Oklahoma Lightning Mapping Array (LMA) and cloud-to-ground (CG) data from the National Lightning Detection Network (NLDN) are examined for each of the events. The flash rate, charge structure and CG lightning polarity are compared to precipitation amounts and signatures from the KOUN WSR-88D polarimetric radar located in Norman, OK. Individual lightning flashes, though infrequent during most of the events examined, quite often extended more than 15-20 km in length. This was possibly due to an increased build-up of charge over an extended period of time before lightning initiation. The differential reflectivity, correlation coefficient, and specific differential phase signatures of regions containing VHF sources are examined to determine if the lightning occurred only in mixed-phase regions and if there are differences in the ice crystal alignment before and after a lightning flash.