Typing Tornadoes by Storm Mode in the Southeast United States

Abstract

Existing work has noted three major, radar-derived, storm modes associated with tornadoes: supercell, quasi-linear convective systems, and tropical systems. I examine the long-term frequency and seasonality of each storm mode between 1996 and 2017 in the Southeast United States. The Southeast is chosen as a focus for this work due to its well-known and unique combination of tornado vulnerability and exposure. Expanding our knowledge of the radar presentation of tornado-producing thunderstorms in this region could assist in the operational interpretation of these events. In this study, a climatology of F/EF1+ tornadoes (1996 - 2017) is generated for the study area (Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas). Tornado counts are then averaged by state from the overall tornado dataset and by storm mode. Finally, the hourly, seasonal, and annual distributions of all tornadoes and tornadoes by storm mode are determined. These results will help in determining the frequency of different storm modes, help the forecasting of tornado events through radar analysis, and help us have a deeper understanding of tornado climatology in the Southeast.