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Experts Upgrade Storm Tracking

As hurricane season approaches, forecasters are looking to new or improved tools to add precision to predictions.

April 15, 2006|Ken Kaye | South Florida Sun-Sentinel

ORLANDO, Fla. — In hurricane forecasting, practice may not make perfect, but technology sure helps.

To improve forecasts this season, which starts June 1, experts plan to draw on an arsenal of upgraded high-tech tools.

Among them: More sophisticated satellite communication gear has been placed on the two P-3 turboprops operated by the National Oceanic and Atmospheric Administration, allowing forecasters to have real-time multidimensional views of storms.

Improved global positioning system devices are to be dropped from NOAA's Gulfstream jet as it circles the periphery of hurricanes, providing a better description of the storm's atmosphere.

Instruments called step frequency radiometers are to be placed on Air Force Reserve hurricane hunter aircraft to help forecasters tabulate storm intensity, one of the most difficult aspects of hurricane forecasting. The devices measure the foaminess of waves to estimate wind strength.

Small unmanned planes called Aerosondes are to be flown into the lowest levels of some hurricanes as they threaten land to collect wind data. Such an aircraft was first used last year in Hurricane Ophelia as it threatened the North Carolina coast. It improved the forecast substantially, officials said.

And eight more buoys are to be placed in the Atlantic to get direct readings of ocean conditions as storms approach.

"Experience is not what matters in developing better forecasts," specialist James Franklin said at the National Hurricane Conference on Thursday. "What does is making improvements to the models and atmospheric observations."

The data from the new equipment will be fed into computer forecast models, helping specialists -- the front-line meteorologists who provide public forecasts -- to make better estimates of storm tracks, intensity and forward progress. The models are tweaked each year to improve their accuracy, said specialist Richard Pasch.

The National Hurricane Center in Miami-Dade County has increased the number of specialists from six to 10.

Max Mayfield, director of the center, warns against expecting a perfect forecast.

"We can't expect miracles," he said.

The hurricane center broke accuracy records in its track forecasts for three years straight, but not during the frenetic 2005 season. It came close, however, Franklin said.

Taking into account all 28 storms, the combined 24-hour track forecast error was 69 miles, whereas the long-term cumulative average error is 75 miles. At 48 hours, the error was 122 miles, compared with the long-term average of 136 miles, and at 120 hours, or five days, the error was 329 miles, compared with the long-term average error 348 miles.

The center was more precise in its 2004 predictions.

Franklin attributed the lower accuracy in 2005 to the fact it was a "hard season" with many storms forming farther to the north than usual. "They tend to take more complicated paths," he said.

Still, with the major hurricanes that slammed the U.S. coastline, hurricane forecasters "did fairly well," Franklin said.

Notably, the average 24-hour track forecast error was 48 miles in Hurricane Katrina, 61 miles in Rita and 48 miles in Wilma.

The hurricane center continues to struggle with intensity forecasts. Its average error last year was about 23 mph, the same as it was in 1970, said hurricane specialist Lixion Avila. The problem, he said, is forecasters can't predict when a system will rapidly strengthen. Several storms did so last year, including Katrina, Rita and Wilma.

If that intensification happens near the U.S. coastline, as was the case with Hurricane Charley before it struck Punta Gorda, Fla., in August 2004, it can be a "nightmare," Avila said.

"That's why when we tell you that a hurricane is forecast to be a Category 2, get ready for a Category 3," he said.

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