March 19, 2005

Hurricane Center to Offer Probability Map

MIAMI (AP) -- The National Hurricane Center hopes to discourage residents from relying too much on that skinny black line in forecasts by offering a new map that shows the probability of an area being hit.

The color-coded map will display the odds that a given area could face hurricane- or tropical-force winds. It also will try to project a storm's size and intensity. The center will post the map on its Web site when the Atlantic hurricane season begins June 1.

Gulf Coast residents were caught off guard on Aug. 13, when a Category 4 Hurricane Charley slammed into Punta Gorda. The black line drawn on maps by forecasters hours earlier showed a Category 2 storm hitting Tampa, about 100 miles to the north.

Hurricane specialist James Franklin said 24 hours before landfall, the probability of Charley's core hitting Tampa or Port Charlotte was the same: 30 percent.

"If people had been looking at this probability product rather than focusing on the line, nobody would have come to the conclusion they were safer in Port Charlotte than Tampa," Franklin said.

The hurricane center is considering getting rid of the skinny black line, or projected path, and replacing it with circles or dots to emphasize a much broader cone of uncertainty.

In 2004, the National Hurricane Center achieved its best accuracy record in its track forecasts of nine hurricanes, five tropical storms and one subtropical storm.

The center's average track error was 67 miles when the systems were 24 hours away, a marked improvement over the 10-year average error of 90 miles. Those errors are half what they were 15 years ago.

The steady improvement is the result of more sophisticated computer forecast models, as well as more and better information about the atmosphere that surrounds hurricanes, Franklin said.


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