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Forecast accuracy also has downside

Even as weather forecasts get more accurate, the message doesn't always get through clearly to residents.

MIAMI - The National Hurricane Center is sometimes the victim of its own success.

As its forecasts grow more accurate every year, residents put more faith in them. So even the smallest errors lead residents to question why the predictions were off.

"They know we have aircraft and fast computers, and a lot of people think we do a lot better job than we actually do," said Max Mayfield, the hurricane center's director. "And we have tried to stress every chance we get that we have uncertainties in forecasting, especially in forecasting intensity."

And even when the meteorologists are right, the message sometimes doesn't get through clearly to residents. Some then blame the forecasts as misleading.

Hurricane Wilma is a prime example. The hurricane center said before Wilma came ashore Oct. 24 that the best estimate was that it would hit as a Category 2 hurricane, but warned it could be a major Category 3 storm.

It turned out their warning was right, and Wilma hit Florida's southwest coast as a major hurricane. But Wilma weakened as it crossed the state, and likely had sustained winds of Category 1 (74-95 mph) strength over most of the hard-hit areas of Miami and Fort Lauderdale, forecasters said in preliminary reports. Isolated places may have had Category 2 winds (96-110 mph).

But many people thought that Wilma was still a Category 3 (111-130 mph) when it hit the state's east coast.

"They made it seem like it would be a Category 2 or maybe a 1. That's why everybody is just so unprepared," said Carolyn Wilson, a 44-year-old nurse from Fort Lauderdale.

A researcher who studies residents' behavior during hurricanes said those misconceptions are often common.

"I would be surprised, frankly, if a majority of people were familiar with the details of the forecast," said Jay Baker, a geography professor at Florida State University. "I think that they rely on their local emergency management to distill the forecast into operational terms for them," such as whether to evacuate or put up shutters.

Surveys show that people pay much more attention to hurricanes when an evacuation order is issued, no matter the warnings that meteorologists give, he said. Broward County - home to Fort Lauderdale - and Miami-Dade County issued mandatory evacuation orders only for mobile home residents.

A surprising number of people underestimate the destructive power of hurricanes, Baker said.

In parts of Miami-Dade and Broward that are in evacuation zones because they could be flooded by even the weakest hurricanes, nearly a third of residents think they would be safe at home in a Category 4 storm with sustained winds of 155 mph.

"People need to be told specifically what they need to do rather than how strong it will be," Baker said.

Mayfield understands that people may look for more exact descriptions of the damage each hurricane will cause, but he said the Saffir-Simpson scale of ranking hurricanes from Category 1 to 5 has proved to be an efficient, simple warning system since its creation in 1969.

"You don't want to have it so complicated that no one understands it. ... If there's a better way to do it, we're sure open to suggestions," he said.

David Striegold, a 44-year-old pool serviceman from Davie, which is in Broward County, praised forecasters for their "fine job" in keeping the public informed about Wilma's potential and said people need to understand that weather is unpredictable.

"It's Mother Nature - how could it be set in stone?" he said.

Mayfield said he has received many e-mails from people congratulating the hurricane center's forecasts for Katrina, Rita and Wilma during the busiest hurricane season on record, which ends Nov. 30.

"I usually pass those along to the staff and say, "Enjoy the kudos, but remember we've got a month to go and you're only as good as your last forecast,"' he said.

[Last modified October 31, 2005, 03:00:27]