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Hurricane Isabel, weakened slightly but still a strong storm, continued chugging westward Saturday, with forecasters starting to mention North Carolina as a possible destination.

Isabel, with top sustained winds of 150 mph, was centered Saturday morning about 450 miles northeast of Puerto Rico and was moving west at about 9 mph.

Lixion Avila, a hurricane specialist at the National Hurricane Center in Miami, said the 150 mph winds "might be on the high side," but he added that the storm "remains very dangerous."

Avila said minor fluctuations in strong hurricanes are common, and that forecasters had expected Isabel to weaken somewhat from its 160 mph winds of Friday. It is now a Category 4 storm in the Saffir-Simpson rating scale of hurricanes, which ranges from 1 to 5.

Forecasters agree that Isabel will remain north of Puerto Rico, the Virgin Islands and even the Bahamas. So the big question remains: What impact will the hurricane have on the eastern United States?

Avila said one of the key computer models used by the National Hurricane Center indicates "the hurricane will be near the coast of North Carolina in five to six days," meaning Thursday or Friday.

Yet another key model predicts Hurricane Isabel will curve northward, and either strike the Maryland-Delaware area or even farther north, perhaps between Long Island and Cape Cod.

For the first time officially, forecasters are saying that none of the computer forecasts indicate Florida is at risk of a direct hit from the hurricane.

Larry Cosgrove, with the private meteorological firm Weather America, has predicted for several days that Isabel will strike Friday morning, somewhere between Myrtle Beach and Wilmington, then move inland across Fayetteville and between Greensboro and Raleigh. He predicts the storm will swing northward, spreading heavy rain, strong winds and tornadoes across the Washington and New York City areas.

Several other forecasters say they are leaning toward a strike somewhere between Georgetown, S.C., and the Outer Banks.

In such a scenario, the Charlotte area would escape with light to moderate rain and winds far below storm status.

The storm currently is being steered westward by clockwise winds at the bottom of a large high pressure system over the North Atlantic.

Forecasters say a slight weakness on the west side of that ridge should allow Isabel to swing northwestward late this weekend or early next week.

If that weakness were to remain, the hurricane would move northward, off the Carolinas coast, and not affect the Southeast.

However, most forecasts indicate the high pressure system over the North Atlantic will re-strengthen Monday or Tuesday, thereby guiding Isabel back to the west – toward land.

Isabel's winds are expected to remain strong – at least 125 to 130 mph – throughout the next three to five days. Forecasters say it will spread large waves and dangerous rip currents across Puerto Rico and the Virgin Islands this weekend and early next week.

Hurricane Strength

Meteorologists measure the intensity and potential damage of hurricanes using the Saffir-Simpson scale.

Category 1: Winds of 74-95 mph, storm surge 4-5 feet above normal, no substantial building damage. Threat mainly to unanchored mobile homes, shrubbery and trees.

Category 2: Winds of 96-110 mph, storm surge 6-8 feet above normal, some roofing material, door and window damage of buildings. Considerable damage to mobile homes and piers.

Category 3: Winds of 111-130 mph, storm surge 9-12 feet above normal, structural damage to small homes and buildings, large trees blown down, mobile homes destroyed, flooding near coast. Evacuation within several blocks of the shoreline may be required. (Fran, 1996, North Carolina.)

Category 4: Winds of 131-155 mph, storm surge 13-18 feet above normal, roofs blown off houses, destruction of mobile homes, major damage to lower structures near the shore. Flooding may require evacuation up to six miles inland. (Hugo, 1989, South Carolina.)

Category 5: Winds greater than 155 mph, storm surge greater than 18 feet above normal, some homes and buildings destroyed, major damage to lower floors of all structures less than 15 feet above sea level and within 500 yards of the shoreline. Evacuation within 10 miles of the shoreline may be required. (Andrew, 1992, South Florida.)