MIAMI -- Hurricane Isabel's sustained winds increased to 160 mph Saturday as the Category 5 hurricane swirled ominously closer to the East Coast.
The hurricane had earlier been lowered to a Category 4 storm when winds fell to 150 mph. It was reclassified after a hurricane hunter plane flew into the eye to measure its intensity Saturday afternoon. A hurricane hits the top of the Saffir-Simpson hurricane scale when its winds reach 156 mph.
The slow-moving, powerful storm was still several days from land, and forecasters were unsure if it would strike the United States. However, computer models predicted it would turn toward the Carolinas over the next five days.
"It's not definite, but things are looking more ominous than yesterday for the East Coast," National Hurricane Center meteorologist Eric Blake said Saturday.
At 11 p.m. EDT, Isabel was centered about 350 miles north-northeast of San Juan, Puerto Rico and moving west-northwest at 12 mph. Forecasters expected it to continue that movement into Sunday.
Large ocean swells and dangerous surf conditions were forecast for the Leeward Islands in the northeastern Caribbean. And the U.S. State Department issued a travel warning Friday advising tourists to avoid the Bahamas because of the storm.
The long-range forecast placed Isabel farther north than previously thought. Now, experts at the National Hurricane Center in Miami say it could be centered roughly 100 miles south-southeast of Maryland's Chesapeake Bay by Thursday evening, if it makes a predicted turn to the northwest. But hurricanes can be unpredictable, and long-range forecasts have large possibilities for error.
Forecasters said Hurricane Isabel could still strike anywhere on the Atlantic coast, and officials warned residents to be alert. They expected to know more about the potential direction of the storm late this weekend.
"If you've been lax with your hurricane preparations, now's a really good time to catch up," Blake said.
Some residents along the East Coast were taking that advice, buying water, plywood and other supplies just in case Isabel made landfall.
"They don't want to get caught with their pants down," said Steve Myers, who sold plenty of plywood - despite the highest prices in a decade - at the 84 Lumber he co-manages in Georgetown, S.C. A half-inch-thick sheet now costs about $20, but that's "cheaper than a $300 window," Myers said.
In coastal Georgia, the Chatham County Emergency Management Agency encouraged people to review their hurricane plans, which should include adequate supplies, updated insurance coverage and evacuation routes.
"It's still a long ways away (but) we have to prepare as if it's coming here," said agency director Phillip Webber.
South Carolina Gov. Mark Sanford and other state officials were briefed Saturday by the state Emergency Management Division on emergency preparations. The state went on an elevated alert status Friday.
Water management officials in Florida were also worried about some of the already-swollen rivers and lakes because a direct hit from a hurricane could cause severe flooding.
National Guard officials in the Southeast said enough troops were ready to help if necessary, despite mobilizations in Iraq and other parts of the world.
The last Atlantic hurricane to develop into a Category 5 storm was Mitch in 1998, which killed about 11,000 people in Central America.
The last two Category 5 hurricanes to strike the U.S. coast were Andrew in 1992 and Camille in 1969. Andrew, still the most expensive natural disaster in U.S. history with a $30 billion damage toll, tore through south Florida and Louisiana, killing 43 people. Camille killed 143 on the Gulf Coast and 113 in Virginia flooding.
The Atlantic hurricane season began June 1 and ends Nov. 30.
On the Net:
National Hurricane Center: http://www.nhc.noaa.gov