NASA Scientists Are Studying Lightning to Predict Hurricane Intensity

Can studying lightning help us predict hurricane? A team of NASA scientists discovered a new method to predict incoming storms, as well as hurricane intensities.

Generally, increase in lightning within the storm signals entails a strong storm coming. However, it was recorded that even weakening hurricanes occasionally have large lightning outbreaks as well.

Lead researcher Patrick Duran and his colleague published in Geophysical Research Letters their study on evolution of lightning flash density, flash size, and flash energy during the 2019 Hurricane Dorian. They focused on analyzing the lightning outbreaks in Hurricane Dorian using the Geostationary Lightning Mapper (GLM) to understand intensity of incoming hurricanes and determine what a lightning outbreak really indicates for predicting intensity. With GLM's capability of detecting size and energy of lightning flashes, even in open oceans, getting information from lightnings in hurricanes was made possible.

Lightning outbreaks can be larger when storms intensify

Upon studying the 2019 Hurricane Dorian, Duran discovered that when the storm intensifies, its lightning flashes were larger and more dynamic than when the storm has weakened.

Hurricane Dorian was the first major hurricane of the 2019 Atlantic hurricane season which reached Category 5 intensity while it made its landfall in Elbow Cay, Bahamas, and weakened to Category 1 intensity as it turned northeast.

Duran and his team used the GLM to examine the two most distinct inner-core lightning outbreaks in Hurricane Dorian. The first outbreak happened during Dorian's intensification along with a rapid intensification (RI) increased in 30 kts (35 mph) in sustained winds over 24 hours. They had observed during rapid intensification that the inner-core lightning flashes rose as it condensed in the radius of maximum wind.

The second outbreak, which happened during the weakening, had recorded multiple flashes within the radius of maximum wind - with a rate thrice of that during the rapid intensification. Scientists said this signal should be incorporated with strengthening, but it was characterized with smaller and less active flashes instead.

Location of lightning flashes affects storm's intensity

The team aims to continue further observations of lightnings across most of the western hemisphere, including the Atlantic and Eastern Pacific tropical basins using the GLM sensor. This instrument helps them measure changes in cloud top radiance created by lightning. GLM sensor can also detect flash location, average flash area and total optical energy which gives researchers a number different unique perspective in analyzing lightning flashes.

With this special feature, Duran and the team argues that the changes in the lightning's location can determine potential intensity of incoming storm.

"This information provides clues into how storm structure changes at peak intensity and can potentially help forecasters interpret whether a lightning outbreak signifies storm intensification or weakening," Duran added.

To test validity of this new weather prediction method, Duran wishes to analyze numerous storms in the future to differentiate lighting patterns of intensifying and weakening storms. He noted that these patterns are significantly helpful in predicting rapid intensification which is more complicated than intensification alone.