Hurricane Forecasting Remains Cloudy
ON a muggy August afternoon, a P-3 Orion lifts off the runway at Opa Locka airport just north of Miami. Its destination: hurricane Felix, now pounding the Eastern seaboard.
Beyond the immediate task of keeping tabs on the churning storm, the plane and its scientists are key players in the effort to improve hurricane forecasts.
For those who live along America's coastlines, as half the population of the United States does, the accuracy of tracking and forecasting severe storms is crucial. Thousands of lives and millions of dollars hang on the timeliness of hurricane warnings.
The science of forecasting a hurricane season has gotten a modest boost from an approach developed by William Gray, a professor of atmospheric science at Colorado State University in Fort Collins, Colo. Using a range of global climate data, including climate patterns from the tropical Pacific to the west coast of Africa, Dr. Gray and his fellow researchers were able to predict months in advance that 1995 would be the biggest hurricane year in two decades.
This approach allows Gray to estimate the number and intensity of Atlantic hurricanes and tropical storms during a given season, which runs from June 1 to Nov. 1. The most intense period of this season runs from mid-August to mid-October.
Earlier this month, the team updated its June forecast, boosting from 12 to 16 the number of tropical storms for 1995. The number of hurricanes rose from eight to nine, three of which could become major or severe.
"Gray's approach has proven out," says Ed Zipser, a professor of meteorology at Texas A&M University in College Station, Texas. "The problem with it is that it says to the National Hurricane Center, 'Get ready for a busy summer,' but it doesn't say who will get hit."
At the level of individual storms, forecasting gets cloudy.
"We understand enough to describe what happens [in a hurricane], but we need to understand more to make more-accurate predictions," says Hugh Willoughby, acting director of the hurricane research division at the National Oceanic and Atmospheric Administration's (NOAA) Atlantic Oceanographic and Meteorological Laboratory in Miami.
For example, researchers still cannot explain adequately why some tropical waves and depressions strengthen into tropical storms and hurricanes and others do not.
NOR are they fully settled on what steers hurricanes. In the fall, says Dr. Zipser, large, strong low-pressure systems form that rapidly herd hurricanes northward. But in the summer, the interactions between hurricanes and larger-scale changes in atmospheric circulation become more subtle and complex. Such interactions need to be studied from sea level to as high as 40,000 feet - an expensive proposition given the cost of flying aircraft that can reach that altitude.
Two other aspects of hurricanes demand more focus, some researchers say: understanding the mechanisms behind rapid changes in hurricane intensity, which bears on the size of the storm surge, a hurricane's most dangerous element; and the impact of a hurricane's remains once it makes landfall.
"We haven't a clue if a tropical system will drop 5 inches of beneficial rain over a wide area or will drop 25 inches in a narrow river valley for a killing flood," Zipser says.
In addition, Congress is adding another level of uncertainty. Both houses on Capitol Hill are considering measures to abolish the Commerce Department and dismember NOAA - moves that President Clinton has vowed to veto.
The National Weather Service, which would become part of the Interior Department, would take on NOAA's weather forecasting and research roles.
But it would have to do so on a budget of $495 million, compared with the $624 million it requested for its own scaled-back activities for fiscal 1996. NOAA's facilities would be put on the auction block. The bills are expected to go through revisions after lawmakers return from their August recess.