The Significance of Lightning in Well-Defined Tropical Cyclones (credit: Matt Reagan and American Meteorological Society)
When most people think of hurricanes and tropical cyclones, the first line of thought does not always include lightning. Tropical cyclones are what are known as “warm-core” systems, which mean that the center of the storm is most intense at the surface but then stabilizes with altitude. Because of the significant amount of latent heat that is released within tropical cyclones and the rapid rotation, lightning is not a common feat With all of the news surrounding the ever-evolving Hurricane Dorian in the western Atlantic waters, recent satellite passes indicated the presence of lightning within the inner core of the cyclone. In the subsequent hours, Dorian intensified to a category 4 storm with maximum sustained winds exceeding 130 mph. But how much of a role does lightning play in the intensification of organized tropical cyclones?
One of the first studies in the literature concerning the relationship between lightning and tropical cyclones is from Samsury and Orville (1994) who investigated the lightning characteristics from Hurricanes Hugo and Jerry of 1989. Although their study focused on the quantitative statistics of lightning flashes including parameters such as the polarity, one of the primary results from this study showed that the greatest number of flashes within both storms occurred in the right-front and right-rear quadrants, more specifically within the outer convective rainbands.
Regarding rapid intensification, A study performed by DeMaria et al. (2012) showed that TCs that intensify over time tend to have the greatest lightning densities compared to those that weaken over time. Most recently, Stevenson and Corbosiero (2018) surveyed a total of 10 years-worth of tropical cyclone data fitting between certain criteria for vertical wind shear and sea surface temperature. It was found that most of the inner core lightning bursts (ICLBs from their paper) occurred with intensifying storms (e.g., depressions and tropical storms) and were also a precursor to intensification at a roughly 24-hour lead time prior to the lightning bursts. The symmetricity of convective cores and lightning bursts within intensifying tropical cyclones also was observed to be more prominent than in decaying convection.
So while it is uncommon to see lightning in tropical cyclones, the advent of satellite technologies such as the World Wide Lightning Location Network and the Geostationary Lightning Mapper aboard the GOES-16 and GOES-17 satellites allow for forecasters and researchers to better understand rapid intensification processes. With more research and applications to forecasting practices, detection of rapid intensification events have the potential to become more predictable in the future, leading to more accurate intensity forecasts.
Below are the references for the articles mentioned above:
DeMaria, M., R.T. DeMaria, J.A. Knaff, and D. Molenar, 2012: Tropical Cyclone Lightning and Rapid Intensity Change. Mon. Wea. Rev., 140, 1828–1842, https://doi.org/10.1175/MWR-D-11-00236.1
Samsury, C.E. and R.E. Orville, 1994: Cloud-to-Ground Lightning in Tropical Cyclones: A Study of Hurricanes Hugo (1989) and Jerry (1989). Mon. Wea. Rev., 122, 1887–1896, https://doi.org/10.1175/1520-0493(1994)122<1887:CTGLIT>2.0.CO;2
Stevenson, S.N., K.L. Corbosiero, M. DeMaria, and J.L. Vigh, 2018: A 10-Year Survey of Tropical Cyclone Inner-Core Lightning Bursts and Their Relationship to Intensity Change. Wea. Forecasting, 33, 23–36, https://doi.org/10.1175/WAF-D-17-0096.1
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© 2019 Meteorologist Brian Matilla