Charley a Harbinger of Busy Hurricane Season?
for National Geographic News
|Updated August 27, 2004|
Meteorologists are still examining the data from Hurricane Charley, but the killer storm that slammed into Florida on August 13 made two things clear: Hurricanes can still surprise forecasters, and the rest of the 2004 hurricane season probably is going to be quite active.
Meteorologists expected Hurricane Charley to develop into a major hurricane and come ashore on Florida's west coast at or near Tampa Bay. Residents from Tampa southward to the Florida Keys were warned that the storm posed a serious threat to them. That warning included Punta Gorda, where the storm struck last Friday afternoon.
But Hurricane Charley intensified at an astonishing rate just a few hours before making landfall, and its eye wobbled off its forecast track and smashed ashore about 70 miles (112 kilometers) south of Tampa, killing at least 21.
Charley became the most powerful hurricane to strike the United States since Hurricane Andrew in 1992. It will probably be ranked among the 20 most powerful hurricanes to hit the U.S. since 1900.
The fact that the hurricane did not make landfall exactly where it was predicted to come ashore drew some criticism of forecasters. But a meteorologist who was watching Hurricane Charley's every move noted a touch of irony in the predictions for this storm.
The very accurate forecasts in September 2003 for Hurricane Isabel's landfall in North Carolina may have set up some unrealistic expectations for forecasters trying to anticipate Hurricane Charley's path after it formed in the Caribbean Sea and crossed Cuba as a Category Two storm on August 12.
"Obviously, we were happy about our performance in Isabel, and we want every forecast to be perfect," said James Franklin, a meteorologist at the National Hurricane Center in Miami, who was one of the forecasters working on Hurricane Charley. "But given where we are, in terms of our understanding and the data available, that just isn't realistic. We may have raised expectations too much with that very publicized Isabel landfall."
Meteorologist Steve Lyons of the Weather Channel said all of the factors that aided Hurricane Charley's rapid intensificationincluding very warm water in the Gulf of Mexico and minimal upper-level winds (known as wind shear) that would have hindered its developmentwere in place soon after the sun came up on August 13.
The storm raced up the Saffir-Simpson scale as it moved parallel to the west coast of Florida. The scale rates hurricanes from Category One to Category Five according to their wind speeds and destructive potentialWhen a hurricane achieves winds of 111 miles an hour (178 kilometers an hour), it is classed as Category Three on the scale and is considered a major hurricane.
At 11 a.m. on August 13, Hurricane Charley was rated a Category Two, meaning that it had winds between 96 and 110 miles an hour (154 to 177 kilometers an hour). By 4 p.m. that same day, the winds around the storm's eye had reached 145 miles an hour (233 kilometers an hour), making it a Category Four storm.
Hurricane Charley may have made the jump from Category Three to Category Four in only one hour. "I suspect this isn't a record (for intensification), but it's certainly up there," Franklin said.
When a hurricane undergoes rapid strengtheningsometimes called bombing outjust before it makes landfall, it creates a worst-case scenario for forecasters and coastal emergency management officials. And once a hurricane begins bombing out, it can build up an unstoppable momentum.
"When a hurricane intensifies, it's like a snowball rolling down a hill, increasing in size," said meteorologist Joe Bastardi of AccuWeather, a commercial weather forecasting service. "If it gets everything going right, it can ramp up quickly."
Some of the most notorious hurricanes in U.S. history have cranked up a murderous punch just as they were about to come ashore. The last time it happened was 1992, when Hurricane Andrew climbed from a Category One to a Category Five storm in only 30 hours before making landfall south of Miami.
The rapid increase in Charley's strength was a bit of a surprise to forecasters, although they knew it would become a powerful hurricane.
"It could have become a Category Five if it had had another six hours over water to develop, but of course we'll never know for sure," Lyons said. "Rapid intensification is always somewhat of a surprise, since most typical hurricanes (increase by) about 10 or 20 miles an hour (16 or 32 kilometers an hour) per day."
Phil Klotzbach, a research meteorologist at Colorado State University, said the fact that hurricanes already are forming east of the Leeward Islandswhich are located at the northeast edge of the Caribbean Seais an ominous sign. "When we get storms forming east of the islands in August, it tends to mean that conditions are ripe for an active season," Klotzbach said.
September 10 is considered the peak of the hurricane season, when storms are most likely to form.
Before the start of the 2004 hurricane season, renowned forecaster William Gray of Colorado State predicted three major hurricanes would form. Since July 31, four hurricanes have formed, and two of themAlex and Charleyhave become major storms.
Hurricane Forecast Unchanged: Busy Season
"The forecast that we issued a couple of weeks agothat it would be a busy season overallI don't see anything to change that at this point," said Chris Landsea, a meteorologist at the U.S. National Oceanic and Atmospheric Administration in Miami. "The Atlantic and the Caribbean have warmer than normal water temperatures, and there's lower wind shear. It will not be that busy every single day as it has been for the last two weeks, and I wouldn't be surprised if it calms down [briefly]."
Meteorologists think hurricane cycles wax and wane over several decades. From 1920 to 1959, 73 hurricanesincluding 30 major stormsstruck the United States.
The activity diminished between 1960 and 1999. During that period, 57 hurricanes struck the United States, including 21 major storms. While the hurricane cycle was down, the population dramatically increased on the Atlantic and Gulf coasts.
But meteorologists think the cycle shifted back to a period of increased activity around 1995. And unlike during the active period during the first half of the 20th century, there are millions more people living near the ocean today.
That means that if hurricanes again prowl the coastal waters in a week or two, millions of people will face a torturous decisiondo they stay when a storm is near, or do they evacuate?
For the professionals, that's a no-brainer. "People must, must, must be prepared to go to a safe haven," said the Weather Channel's Lyons.
Willie Drye is the author of Storm of the Century: The Labor Day Hurricane of 1935, published by National Geographic Books. He lives in Plymouth, North Carolina.
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