Like a football team that tries to lower expectations even as it keeps winning, hurricane forecasters don’t want their success with Hurricane Isabel to make anyone complacent.
AS DIRECTOR of the National Hurricane Center in Miami, Max Mayfield is proud of his forecasters’ work in warning residents of the Carolinas, Virginia and mid-Atlantic states of the massive storm.
But, he adds: “I worry about the expectation we will do this well on every storm, and that’s not going to happen.”
Nonetheless, the Hurricane Center, part of the National Weather Service, got it right on Isabel. It has been improving its forecasts steadily in recent years and research continues into making them even better in the future — particularly in forecasting the strength of storms as well as their track.
This was the first year the center has issued five-day forecasts of the expected storm track, and those forecasts were more accurate than three-day forecasts of a decade ago. With Isabel, for example, the hurricane’s predicted location in five days was off by about 166 miles. The average three-day forecast of a hurricane’s path was off by more than 200 miles between 1994 and 2002 and 300 miles between 1984 and 1993.
So what’s been happening?
It’s a combination of things, Mayfield said — better observations, better and faster computers, improved computer programs to model the weather and a band of increasingly skilled forecasters.
The predictions for Isabel won praise from Bob Ryan, a former president of the American Meteorological Society who forecasts for WRC-TV in Washington.
“The information we were getting from the hurricane canter and local forecast office was really terrific,” Ryan said.
Elbert Friday, president-elect of the AMS, agreed.
“Even though I lost power and even though I was without water ... I thought the Weather Service did an excellent job of forecasting this particular storm track. It gave the emergency management community very solid time to prepare,” said Friday, a former head of the Weather Service who lives in Northern Virginia.
Helping forecasters in Isabel’s case was a strong high pressure area over the northwest Atlantic Ocean. The wind revolving in a clockwise direction around the high provided a powerful steering current for the storm.
“We’re going to have cases where currents are not as well defined or when they’re changing,” Mayfield cautioned. “You can’t set a record every time you make a forecast.”
Regular flights of the National Oceanic and Atmospheric Administration’s new Jetstream aircraft around Isabel allowed the forecasters to collect data on the steering pattern. Air Force Reserve crews flew C-130 aircraft into the storm to collect data, and NOAA crews flew P-3 aircraft.
Those planes dropped measuring devices that radioed back wind, temperature, humidity and other information every half-second, providing a mass of data that was fed into computers that analyzed the storm and predicted its movement.
That’s a far cry from years past when hurricane forecasters relied on reports from coastal areas and ships at sea. Indeed, in 1938 a deadly hurricane approached Florida then turned north. Forecasters lost track of it until it slammed into Long Island and New England, claiming more than 600 lives.
Scientists are working on improving mathematical models of how the storms behave, change intensity and interact with wind and water. Research is under way at the National Center for Atmospheric Research, National Center for Environmental Prediction, Air Force Weather Agency, Naval Research Laboratory, Federal Aviation Administration, Oklahoma University, and NOAA’s Atlantic Oceanographic and Meteorological Laboratory.
Today, forecasters use a variety of computer models — 10 or 12 “every time we make a forecast,” Mayfield said. “They’re all getting tweaked every year. They get a real ’attaboy’ for improving these models as much as they have.”
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