A Comparison Between Radar and Warning Data Associated with Tropical Cyclone Tornadoes and Waterspouts

Recent research has demonstrated that tropical cyclone (TC) tornado warning skill is reduced compared to non-TC tornadoes. Most TC tornadoes occur near the coast, where conducive conditions for supercells exist over both land and water. Upon moving onshore, the supercell rotation often strengthens, likely due to increased friction over land. Overland TC tornadoes are warned with tornado warnings, while tornadoes over the ocean are classified as waterspouts and warned using special marine warnings. However, no prior studies compare TC tornadoes and waterspouts. As a first step, this study analyzes the climatological and radar characteristics associated with tornado and waterspout reports from landfalling TCs in 2013-2023. Initial results indicate that the tornadic mesocyclones contain stronger low-level rotation and greater convergence than those with waterspouts. There is a small sample of waterspouts with convergence and low-level rotation as strong as the TC tornadoes. These results may be attributed to increased friction on land, or suggest different dynamical processes among TC waterspouts. In a TC-relative reference frame, tornadoes typically occur in the northeast quadrant, while waterspouts can occur in all TC-relative quadrants. This analysis aims to improve our understanding of supercells for onshore and offshore TC tornadoes.