Application of an improved SCIT algorithm to investigate lightning characteristics of a tornado outbreak in Georgia

The Severe Storms Research Center (SSRC) at the Georgia Tech Research Institute (GTRI) has developed an improved Storm Cell Identification and Tracking (SCIT) algorithm based on DBSCAN clustering and JPDA tracking. This improved algorithm is used to associate National Lightning Detection Network (NLDN) cloud to ground (CG) and intracloud (IC) lightning data to individual storm cells during a tornado episode which occurred in north Georgia on March 15, 2008. During that day, three tornadoes affected north Georgia, including an EF3 tornado which caused two fatalities.

The improved algorithm is used to associate NLDN data with individual cells embedded in a complex mesoscale system. This allows the type of lightning (CG vs. IC), as well as stroke polarity to be examined as a function of cell evolution and strength. The electrical evolution of several tornadic and non-tornadic cells is examined and compared.