Long range lightning nowcasting applications for tropical cyclones

Vaisala has been operating a long range lightning detection network (LLDN) since 1996. This network detects cloud-to-ground (CG) lightning over oceanic and land areas that are many 1000s of kilometers from existing network sensors. Although the detection efficiency and location accuracy of the LLDN varies with region and time of day, the data from this network provides continuous monitoring of lightning activity over a large portion of the Atlantic and Eastern Pacific tropical cyclone basins.

Currently, long range lightning data is mainly used by the aviation community for nowcasting oceanic convection. However, there are many potential meteorological applications of long range lightning data for nowcasting tropical cyclone development. Lightning activity can be used to help identify and follow the evolution of the most intense outer rainbands. It can help identify bursts of deep convection with large updraft speeds near the center of the storm that may play an important role in hurricane intensification. These bursts of convection near the storm center have often been associated with the improved organization of a tropical storm as it attains hurricane status and with primary and secondary eyewall formation and contraction. Other phases of the hurricane lifecycle have also been associated with lightning outbreaks near the center of hurricanes.