With weather forecasters all but certain Hurricane Isabel will strike the central Atlantic coast late this week, state and local governments up and down the eastern seaboard are bracing for what is expected to be an extremely dangerous storm.

Computer models showed that a region from New Jersey to North Carolina was at highest risk for a direct hit, with Washington nearly dead center in the storm's projected path, the National Oceanic and Atmospheric Administration reported on Sunday.

Michelle Mainelli, a meteorologist for the administration's National Hurricane Center, said the most recent forecasts showed tropical-storm-force winds lashing the coast of North Carolina early Thursday and hurricane-force winds of 71 miles per hour or more striking Maryland's Chesapeake Bay area later that day. The hurricane could veer as far north as New York and New England or as far south as South Carolina. And weather experts acknowledged that storms could hold surprises.

But for the first time in the eight days in which federal officials have issued advisories about the storm, they said there was almost no chance it would miss the coast entirely.

"Everything points to a landfall," Mainelli said.

South Carolina remained on "high alert," as Gov. Mark Sanford was briefed by state emergency preparedness officials and weather experts several times during the day Sunday, said his press secretary, Will Folks.

"As long as the hurricane is projected to land within 100 miles of the South Carolina coast, it's a threat," said Folks. "We're hoping some time in the next 24 hours we'll have a better idea of where it'll go."

Forecasters said they expected Isabel to weaken slightly as it neared land, falling from a Category 5 or 4, the two most destructive classes of hurricane, to a Category 3 storm.

Joe Bastardi, a meteorologist and hurricane expert for Accuweather.com, said that would not be a reason to relax.

"As it comes ashore, a storm like this will expand as it weakens," Bastardi said, "pulling more and more energy into it and becoming a much more extensive storm."

The hurricane sustained winds of 160 to 140 miles per hour as it churned through the south Atlantic last week. On Sunday, it registered winds of 155 miles per hour, just 5 miles per hour shy of a Category 5 rating, as it roiled slowly westward, about 300 miles north of Puerto Rico.

The National Hurricane Center has not yet issued a hurricane warning, and no areas have been evacuated, but emergency-management teams up and down the coast on Sunday watched the storm's progress warily and went over emergency evacuation procedures.

Some states may reverse the traffic flows on major coastal roadways to accommodate what will probably be "a mass exodus," said Stephen Leatherman, director of the International Hurricane Research Center at Florida International University in Miami. Virginia's Interstate 64 and South Carolina's Interstate 26 would both flow only westward if a storm strikes, state officials said.

The South Carolina State Emergency Operations Center, originally set to open Sunday, delayed operations until today

About 30 people will work 12-hour shifts to monitor the hurricane, although that number may increase, depending on the storm's path, officials said.

"Everything will flex," said Joe Farmer, public information director for the S.C. Emergency Management Division. "If the storm speeds up or gains intensity or moves toward South Carolina, we bring more and more people into that emergency operations center."

On the Outer Banks and elsewhere in North Carolina, official decisions about coastal-county evacuations were being held off until today or Tuesday. But some residents were already taking precautions.

Delaware Emergency Management officials were concerned about Isabel's potential impact on next weekend's NASCAR races at Dover International Speedway and the flocks of 200,000 fans -- more than six times the population of Dover -- expected to arrive at the races.

Leatherman said more people seemed to be preparing for a brush with Hurricane Isabel than they did in 1999, when Hurricane Floyd crashed into the Carolina coast. Leatherman said he had heard reports that hardware stores were running out of plywood.

"People are taking this one pretty seriously," Leatherman said. "It's almost the perfect hurricane. It's like a top out there turning 160 mph round and round."