New system foresees fewer storms

A British method uses computer models, not statistics as in the U.S.

By CURTIS KRUEGER
Published June 23, 2007

The next big thing in hurricane forecasting may be the new system just released by the British government, which calls for a lighter storm season than others have predicted this year.

The British equivalent of the National Weather Service - called the Met Office - this week predicted seven to 13 hurricanes would form in the Atlantic region in the five months starting July 1. It's the first time the British agency has issued a tropical storm outlook.

Julian Heming, a tropical prediction scientist with the Met Office, said in a telephone interview that the British agency's new model could take some of the subjectivity out of hurricane forecasting.

But well-known hurricane researcher William Gray of Colorado State University said he's skeptical about whether the new model will work.

"I wish them well. People have been saying this is the wave of the future, " Gray said. But he added, "I have very little hope for this method."

In the Met Office approach, data about the oceans and atmosphere are fed into a computer to paint a global picture of what's currently happening in the world's seas and skies, Heming said. Then they use computer simulations to carry this picture forward in time, to learn how the seas are cooling or warming, how wind patterns are changing, and how many tropical storms are likely to form in the coming months.

That means the analysis is left more to the computers studying the data, and less to human interpretation, Heming said. He called the new system "a numerical model, rather than looking back at the past history."

Gray and others use a statistical approach by comparing the recent meteorological data to past years to see whether the coming hurricane season is likely to be a busy one or a slow one.

Gray and colleagues predicted 17 named storms for the full season, including nine hurricanes. The National Hurricane Center in Miami predicted 13 to 17 named storms for the six months starting in June. Because two named storms already have formed this year - Andrea and Barry - that would leave 11 to 15 more for the five months covered in the British forecast.

Gray thinks the complexity of the British system will prove to be its flaw, because it requires so many predictions on so many aspects of constantly changing weather patterns and sea conditions.

"The atmosphere is so complicated, so involved, that you just can't write code and go three to six months in the future, " Gray said.

Gray said even if the Met Office forecast proves more accurate this year, it will take time to make sure those results weren't just a fluke, because "there's many wrong ways to the right answer."

But Met Office officials believe they have found the right way to the right answer. They said they have been running their model the past two years without publicizing the results, and that it has proved highly accurate.

The United Kingdom doesn't get hit by dangerous hurricanes in the same way Florida does, so why did the Met Office come up with this prediction? Heming said it grew out of forecast methods the agency already uses in cooperation with other agencies in Europe.

He said other world climate experts are studying this type of forecasting as well, to see if it can improve on existing methods.

Curtis Krueger can be reached at ckrueger@sptimes or 727 893-8232.

[Last modified June 23, 2007, 00:01:47]