Striking discovery: A new study has found a correlation between lightning activity and hurricane or cyclone wind speed.
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SYDNEY: An increase in lightning strikes has been found to foreshadow a peak in cyclone or hurricane intensity, a correlation that could help improve predictions of the strength of these storms.
Israeli scientists report in Nature Geoscience today that they analysed 58 hurricanes and found a positive relationship between lightning frequency and maximum wind speed in 56 of them.
In addition, for 70%, lightning activity peaked about a day before the storm did.
Preparing for storms
“If we see an increase in lightning activity, this foretells the intensification of the hurricane and thus can help emergency services better prepare for the coming storm,” said Yoav Yair, study co-author and atmospheric scientist with the Open University of Israel in Raanana.
Meteorologists can now predict the path of hurricanes relatively accurately, but forecasting their strength has remained problematic. These storms are born out over tropical oceans, and directly measuring them is difficult.
The Israeli researchers said that data on lightning could now provide a new way to measure developing hurricanes. The World Wide Lightning Location Network (WWLLN) continuously monitors lightning activity across the planet, using GPS-based networks of detectors, and could be adapted for the purpose, said Yair.
The study analysed all category four and five hurricanes worldwide between 2005 and 2007. Those are the two strongest categories; category four storms require a minimum wind speed of 210km/h and category five storms exceed 249km/h.
In comparing lightning activity with hurricane wind speed, the researchers found a correlation between the two. The surprise, Yair said, was that lightning activity often peaked hours before winds reached their strongest point.
“In essence one might say that lightning activity precedes the fastest winds by one day,” he said.
Welcome technique
Other experts are less confident about the power of the technique to make accurate forecasts, though.
John McBride, with the Bureau of Meteorology Research Centre in Melbourne, Australia, said that predicting cyclone intensity is a significant problem.
However, he called the promise that lightning activity could assist with the predictions “extremely misleading at this stage of development… there is no overall simple relationship that can be applied over a range of different cyclones,” he said.
Kevin Walsh, a meteorologist with the University of Melbourne who studies cyclones, said the work is interesting, but noted that the paper doesn’t detail exactly how the correlation could be used for practical forecasts.
However, “we are not strongly skilled at intensity forecasting for tropical cyclones, so any technique that might be helpful in this regard is welcome,” he said.
