A CASE STUDY OF A POSITIVE STRIKE DOMINATED SUPERCELL THUNDERSTORM THAT PRODUCED AN F2 TORNADO AFTER UNDERGOING A SIGNIFICANT CLOUD-TO-GROUND LIGHTNING POLARITY SHIFT

Shortly before 1700 UTC on 16 December 2000, a relatively low topped supercell moved into Lauderdale County, Mississippi and produced an F2 tornado with a twelve mile track. The tornado was the first to form on an active severe weather day which later produced 12 tornadoes in Alabama, including an F4 tornado in Tuscaloosa County from the same supercell that produced the tornado in Lauderdale County. Prior to the tornado formation, the supercell exhibited interesting cloud to ground lightning signatures, including a significant polarity reversal from positive to negative. The primary focus of this paper will be a discussion of the utility of lightning data to help improve the tornado warning process for the initial tornado touchdown from a Positive Strike Dominated low topped supercell thunderstorm. 1