Lightning and Radar Characteristics of Tornadic Cells in Landfalling Tropical Cyclones

Tropical cyclone (TC) tornadoes are often associated with lower-skill forecasts compared to midlatitude supercellular tornadoes. Forecasts may be improved through a greater understanding of their lightning and radar signatures. This study investigates the lightning and radar characteristics of TC tornadic cells for comparison with TC non-tornadic cells (i.e., strongly rotating cells without tornadoes) and non-TC tornadic cells using three lightning networks and radar data. These results show that the majority of TC tornadic and non-tornadic cells are not associated with lightning, although the former subset occurs with lightning more often. TC tornadic cases typically have lightning maximized to its northeast, whereas the non-tornadic subset is associated with a lower density of flashes that are more symmetrically distributed. TC tornadic mesocyclones also show stronger low-level rotation and convergence at the time of tornado occurrence compared to non-tornadic cases. Hourly trends in rotation and convergence show stronger increases before tornado occurrence in both variables for TC tornadic mesocyclones, yielding small, nonsignificant differences with non-TC tornadic mesocyclones during tornado occurrence. Finally, analysis of lightning throughout the TC shows that tornadic cells often occur on the downwind edge of a broad lightning maximum, whereas non-tornadic cases occur in the middle of a weaker lightning maximum, with these maxima propagating away from the TC in both subsets.