Discriminating between tornadic and non-tornadic soundings in tropical cyclones

This study documents significant differences between tornadic and non-tornadic soundings in onshore and near-shore environments of landfalling tropical cyclones (TCs). The sounding dataset consists of over 5000 rawinsondes and over 1000 dropsondes deployed within 1000 km of 60 Atlantic tropical cyclones between 1997 and 2008. These data are supplemented with all U.S. tornado reports within 750 km of the same systems. First, a storm-relative climatology of forecast parameters traditionally used to forecast mid-latitude supercells and tornadoes was completed for the onshore (rawinsondes) and near-shore (dropsondes) TC environments, and compared to previous studies. Similarities and differences will be presented at the conference. Second, the onshore soundings were stratified into tornadic (at least one tornado was reported within 185 km and 3 h of the sounding location) and non-tornadic (no tornadoes were reported). Third, the ability of the mid-latitude forecast parameters to discriminate between the stratified dataset was evaluated. Finally, using the stratified dataset, significant differences in stability and vertical shear were documented, and a new TC-specific parameter for forecasting tornado potential was developed. This new parameter, including its development and performance, will be presented at the conference.