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Hurricane forecaster sees another slow season

As if to make up for the slow hurricane season he has predicted this year, hurricane forecaster Bill Gray went ahead Friday and offered his prediction for 1992: just as slow. If that sounds dull, it also sounds safe. The roughly 700 Florida emergency-management officials who heard Gray make his annual prediction at the end of the Governor's Hurricane Conference heaved a collective sigh of relief.

"But that doesn't mean Florida's not going to be hit," Gray told the crowd. "Florida may get clobbered this year."

For the record, Gray expects just four hurricanes to grow from the eight named Atlantic tropical storms he has predicted for the 1991 hurricane season, down considerably from the 1990 season. And of the four hurricanes he has predicted this year, just one would be a big hurricane. The six-month season began June 1.

Gray offered no numbers for 1992, but he said that the global weather forces now working to suppress hurricane formation this year likely still will be active during next year's season.

But even with the numbers down, it's just a matter of time before the big killer hurricanes return, he said. And when they do, Florida is in for a shock.

Recent studies have concluded that a storm the size of Hurricane Hugo would do almost $40-billion worth of damage to South Florida alone. By comparison, the state's annual budget is about $29-billion.

"It's not just the (emergency) preparedness along the coast" that Florida has to worry about, "it's the disruption of the economy that's going to take place when and if these intense land-falling storms start hitting Florida again.

"For instance, when Hugo hit South Carolina, the storm was well forecast. There weren't many people killed, but the disruption of the South Carolina economy has been very great, and it's still going on now," nearly two years after the big storm hit.

Gray, a tropical weather researcher at Colorado State University, said he's confident that the really big hurricanes will return to peninsular Florida because the conditions that suppress them will not last forever. The title of a research paper he recently wrote says it all: Florida's Hurricane Vulnerability _ Hostage to African Rainfall.

Gray collects and charts five global weather phenomena, then plugs them into a formula to make his annual predictions. That sounds simple enough, but it took him years of research to identify the factors and how they affect hurricane formation.

The most recent addition to his equation quickly has become his single-most important factor. He said he thinks that as the seasonal rains of Western Africa go, so goes the Atlantic hurricane season. More rainfall, more hurricanes.

Gray said Florida largely has a drought in Western Africa's Sahel region to thank for having avoided a big hurricane during the past 25 years. Researchers have determined that the multidecade stretches of drought and rainfall are normal for the Sahel.

Gray thinks the rainy cycle spurs the Sahel's plant growth. That, in turn, puts more water into the air as the plants grow and give off water into the air. The extra humidity helps generate more thunderstorms, some of them carried west over the Atlantic Ocean to grow into tropical storms and hurricanes.

The second hurricane-squelching factor is the formation late this summer of the so-called El Nino weather pattern in the eastern equatorial Pacific Ocean, Gray said.

The El Nino is a vast pool of warmer water that periodically forms at the ocean's surface. The water is warm enough to give off energy in the form of heat rising from the water. The heat, in turn, is powerful enough to push prevailing winds east. Over the Caribbean and Atlantic, the winds are often strong enough to shear the tops off storms that might otherwise grow into tropical storms and hurricanes.

The name El Nino is a Spanish name of endearment for the Christ Child. South American fishermen noted that the periodic upwelling of warmer water every few years along the Pacific Coast produced bumper catches, often around the Christmas season. Gray said he is able to predict a relatively quiet season next year because the Sahel drought and the new El Nino still should be factors during the summer and fall of 1992.