The National Weather Service, with a few misgivings, is getting ready to play Jimmy the Greek with hurricane forecasts.
The National Oceanic and Atmospheric Administration has decided to let hurricane forecasters issue the odds that a tropical storm will hit a particular city, similar to the chance-of-rain percentages that are a routine part of daily weather reports.
NOAA has not decided whether to release the hurricane odds publicly, however, and some forecasters are warning against it. Gambling with a potentially deadly storm, they say, is not the same as taking a chance on leaving one's umbrella at home.
The plan is NOAA's response to requests from local and state civil defense officials, who want to base their evacuation decisions on something more precise than their own aching bunions.
Trouble is, some meteorologists say, the science of hurricane forecasting is still pretty much in the bunion stage.
Gilbert Clark, a forecaster at the National Hurricane Center in Coral Gables, Fla., said the center's ability to predict the course of a hurricane is so limited that by the time the odds get up to 50-50 the hurricane is less than 24 hours off shore. By that time, the storm's leading edge, with gale-force winds of 32 to 66 mph and towering storm tides, already would have cut off many escape routes from coastal areas.
When the storm is 72 hours off shore--the time when civil defense officials need to make their emergency plans--the center figures that its margin of error is 400 to 1,000 miles in either direction. The highest odds it can offer at that point are 1 in 10 that the storm will hit a particular place, Clark said.
"A 10 percent chance, when the storm is 72 hours away, is a very high probability," he said. "But we're afraid that the public will decide 10 percent means there's no worry at all."
In any case, the probability forecast is of little use if a storm abruptly intensifies in strength.
In 1935, for example, 376 people were killed in the Florida Keys by a Labor Day storm that developed into a "Force 5" hurricane, with 150 mph winds, in less than 36 hours.
Should a similar storm develop now, the toll in densely populated southeastern Florida could be far higher. A three-year study released recently by the Army Corps of Engineers warned that more than 600,000 people could be trapped between Key West and Palm Beach if a hurricane hit the area.
The Corps' study said it would take more than 31 hours to evacuate the Keys and 22 hours to evacuate Dade County, which includes Coral Gables and Miami.
State officials along the Gulf Coast have complained about complacency among residents as a result of relatively mild hurricane seasons recently, despite a couple of close calls.
Clark suggested yesterday that a little more attention might be in order this year. A broad weather pattern that contributed to a lack of storms last year "is getting ready to end," he said.