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Lightning Warns of Hurricanes' Most Intense Moments?

John Roach
for National Geographic News
April 6, 2009
 
Lightning may help improve hurricane forecasts by signaling when the storms are about to reach peak intensity, according to a new study.

Current satellite and radar technologies can fairly accurately predict a storm's path, but when and how much a storm will intensify are harder to pin down.

What's more, using lightning to predict storm intensity may prove especially valuable in regions that lack hurricane-tracking technology, experts suggest.

"The lightning and wind speeds are fairly well correlated, with the lightning peaking [about 30 hours] before the maximum wind," said Colin Price, a lightning researcher at Tel Aviv University in Israel.

"The lightning gives you a precursor to the development of the hurricane."

Convection Connection

The search for a connection between lightning and hurricane intensity stems from research done in the 1990s. Scientists found that storms intensify over warm waters due to greater vertical convection—the upward movement of heat.

"Somehow the convection of these thunderstorms within the hurricane seems to organize the hurricane better and improve its rotation," Price said.

(Related: "Warming Oceans Are Fueling Stronger Hurricanes, Study Finds.")

Price and colleagues collected data on wind speeds in 56 major hurricanes (Categories 4 and 5) between 2005 and 2007. The researchers then compared this information with global lightning data from a worldwide sensor network.

The lightning network currently picks up only a fraction of global flashes, and coverage is inconsistent, which prevented comparative analysis among the hurricanes.

But Price's team did find a connection between increased lightning and higher wind speed in more than 95 percent of the storms. In more than 70 percent, lightning activity peaked about 30 hours before maximum winds.

The researchers hope further examination of the physics involved in this connection could lead to improved hurricane forecasts.

"Obviously, you can't do anything about hurricanes," Price said.

"But you can evacuate people [before the worst of the storm hits], and you can get better information about the intensification if you track the lightning."

Findings appear in this week's issue of the journal Nature Geoscience.
 

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