NC State researchers’ mild hurricane season prediction holds true

Published 6:39 pm Thursday, November 2, 2006

The nation’s leading hurricane experts predicted a vicious 2006 storm season would spin more than a dozen strong storms out of the Atlantic Ocean, but a milder forecast from a lesser-known team in North Carolina is proving more accurate.

“Almost everyone was predicting another extremely active year — all the big names were saying the same thing,” said Lian Xie, a professor of marine earth and atmospheric sciences at North Carolina State University. “We were taking a chance, a risk. If we were wrong, everybody would be laughing at me.”

The hurricane season officially ends Nov. 30. So far, nine named storms have formed in the Atlantic Basin and five have been hurricanes.

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Using a unique method to analyze water temperatures in the Atlantic Ocean, the N.C. State team predicted five or six hurricanes would form in the Atlantic Basin, and one or two would make landfall along the East Coast.

Meteorology professor and doctoral student Tingzhuang Yan presented the prediction in April during a national hurricane conference in California.

The National Hurricane Center predicted 13 to 16 named storms would form during the Atlantic hurricane season. Top researchers at Colorado State University forecast 17.

The predictions didn’t seem overzealous after a record-setting 2005 season, which produced 28 named storms, including the devastating Hurricane Katrina.

“It’s not that we were smarter than everybody else,” Lian said. “If we were truly smart, we would have said, ’It will be an inactive year.’ But we were closer to the truth.”

Most forecasters include the Gulf of Mexico and Caribbean Ocean in their predictions, but the N.C. State researchers focused on the eastern U.S. coastline.

Looking at the same 100-year data used by most forecasters — sea temperatures, winds and cycles between El Nino and La Nina — Lian and his team noticed a pattern.

The intensity and number of hurricanes in the Atlantic Ocean seemed to hinge on the difference in water temperatures between the north Atlantic and south Atlantic.

When tropical water was warmer than normal in the north and cooler than normal in the south, hurricane activity increased off the eastern U.S. coastline, as did the chances the storms would make landfall.

That’s what happened last year, when Lian and his team predicted that five to six hurricanes would form and two or three would make landfall along the eastern seaboard. Seven hurricanes ended up forming and two made landfall on the East Coast.

This year, when the opposite occurred — cooler tropical water temperatures in the North Atlantic and warmer than normal water temperatures in the south — hurricane activity and the likelihood of storms making landfall decreased.

Jeff Orrock, severe weather coordinator at the National Weather Service’s Raleigh office, said hurricane activity was dampened this year by several factors.

For example, the warm-water trend known as El Nino appeared earlier than expected in the Pacific Ocean and suppressed the formation of storms in the Atlantic.