NORFOLK, Va. - The 2001 hurricane season should be quieter than this year's, with fewer storms than normal. But the chances for a storm to make landfall will be higher, the nation's leading hurricane forecaster said this week.
Several "climate indicators" point to "a significant reduction in next year's Atlantic Basin storms," said Bill Gray, a professor of atmospheric sciences at Colorado State University.
Gray and his team of researchers study a wide variety of climate signals, everything from the path and speed of winds in the upper atmosphere to deep sea currents, water temperature and salinity. They then compare and contrast those measures with the historical record to reach a prediction on hurricane activity and storm intensity.
Nine named storms
For 2001, Gray's group expects nine named storms, with sustained winds in excess of 39 mph. On average, there are 9.3 such storms annually. Of those, five should become hurricanes with winds above 74 mph. Typically, there are 5.8 hurricanes annually. Finally, two of the hurricanes are expected to grow into major storms with winds of 111 mph or greater. There are normally 2.2 severe hurricanes each year.
"We're not as confident about this forecast as we were about last year's," Gray said.
Gray and his colleagues came very close to the mark with their forecasts for the recently concluded season and for 1998.
In December 1999, Gray and his colleagues predicted 11 named storms, seven hurricanes and three intense hurricanes for the season. The season ended with 14 named storms, eight hurricanes and three intense hurricanes.
"This was an active year, in keeping with our predictions of a new era of increased hurricane activity," Gray said. "We think the forecast was a good one and, following on last year's accurate forecast that incorporated some new techniques, we believe that our predictive abilities are continuing to improve."
In 1998, Gray's team predicted 14 named storms, 9 hurricanes and 4 intense hurricanes; there were 13 named storms, 8 hurricanes and 5 intense hurricanes.
El Nino factor
Gray's outlook for 2001 relies heavily on expectations that "a weak to moderate El Nino event should be anticipated" in the Pacific Ocean. With such a warming of Pacific waters, wind patterns aloft will shift into a less-favorable phase for hurricane formation in the Atlantic.
At the same time, however, relatively warm sea surface temperatures in the North Atlantic raise the likelihood that any hurricanes in the Atlantic could make it ashore in the United States.
Gray is forecasting a 63 percent probability - contrasted with a historical 52 percent likelihood - that a hurricane will make landfall somewhere on the coast from Maine to Texas. There's a 43 percent probability that a hurricane will hit the East Coast or Florida's peninsula, he said. The historical average is 31 percent. As for the Gulf Coast, the chance of landfall is set at almost normal: 36 percent versus 30 percent.
This year, Gray's team had called for a 72 percent chance of landfall along the entire U.S. coastline and 54 percent for the East Coast and the Florida Peninsula. Only two tropical storms hit the mainland, both in north Florida. It was the first time since 1994 that no hurricanes made landfall in the United States.
"Our estimate of U.S. landfall by an intense hurricane did not prove correct, but landfall predictions don't work well in any individual year," Gray said. He began issuing the landfall forecasts three years ago and has cautioned that the outlook technique is a formula in progress.
Gray said coastal residents appear to have been very lucky in recent years.
Although the last six years have been the busiest period for Atlantic storms on record, with 23 major hurricanes since 1995, only three have come ashore.
