for National Geographic News
African thunderstorms may hold the key to figuring out why hurricanes form, scientists say.
Seven to ten times a month, a cluster of storms rolls off Africa's west coast and wends its way over the Atlantic Ocean toward the United States.
Scientists are watching these clusters very closely.
"Some are organized and eventually turn into a tropical depression or a tropical storm or a hurricane," said Robbie Hood, a hurricane scientist at the NASA Marshall Spaceflight Center in Huntsville, Alabama.
"And maybe a hurricane that affects the U.S."
Hood is part of a team of U.S. and European scientists strategically positioned between continental Africa and the Caribbean to study why some of these thunderstorm clusterscalled tropical wavesdevelop into hurricanes, while others fizzle out.
"We know that these waves are the seeds of storms, but we don't understand why most of them do not turn in to anything," said Bjorn Lambrigtsen, an atmospheric scientist at the NASA Jet Propulsion Laboratory in Pasadena, California.
Only one out of ten tropical waves develops into a named storm or hurricane, such as tropical storm Chris. Chris, which is rapidly losing strength, is the third named storm of the 2006 Atlantic hurricane system.
But the African thunderstorms account for 60 percent of all named tropical disturbances and 85 percent of all major Atlantic hurricanes, according to Jason Dunion, a hurricane researcher with the U.S. National Oceanic and Atmospheric Administration (NOAA) in Miami, Florida.
"These seedlings are an important piece of the Atlantic hurricane puzzle," he said.
(Related story: "Hurricane Forecast: 'Very Active' Season, Five Major Storms Expected" [May 31, 2006].)
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