Eyewall lightning outbreaks and tropical cyclone intensity change

Eyewall lightning outbreaks have been observed in numerous tropical cyclones dating back to the late 1980s using Vaisala's National Lightning Detection Network (NLDN). Many of these lightning outbreaks were observed only when the center of the tropical cyclone was within several hundred kilometers of the U.S. coastline due to the limited detection range of the NLDN. More recently, eyewall lightning outbreaks have been observed over large portions of the Atlantic, East Pacific, and other tropical cyclone basins using datasets such as Vaisala's Long Range Lightning Detection Network (LLDN) and most recently Vaisala's new Global Lightning Dataset (GLD360).

Outbreaks of eyewall lightning have been observed during time periods of intensification, weakening, and little intensity change. The lack of a clear pattern to and understanding of eyewall lightning and storm intensity has made it difficult to use lightning information in operational settings to improve intensity forecasts. Recent research at the National Hurricane Center (NHC), University of Hawaii, and Vaisala has found a recurring lightning signal during a specific portion of the tropical cyclone lifecycle. Anomalous outbreaks of lightning activity frequently occur in the eyewall of tropical cyclones near the end of rapid intensification and maximum storm intensity. This signal has been observed in many Atlantic and East Pacific tropical cyclones and other tropical cyclones around the world. Examples will be shown from Katrina (2005), Rita (2005), and Wilma (2005) in the Atlantic; Rick (2009) in the East Pacific; and Ului (2010) in the Southwest Pacific.