Still shaken by Tuesday’s earthquake, the Washington area braced Wednesday for Hurricane Irene, which threatened to wreck the plans of weekend beachgoers and disrupt the Martin Luther King Jr. Memorial dedication Sunday on the Mall.

The powerful hurricane was expected to dump several inches of rain on the area Saturday as it churns along the Atlantic Coast.

And although it was still hundreds of miles away, meteorologists said it could produce stormy and treacherous conditions along the beaches of North Carolina, Maryland, Delaware and New Jersey as it passes.

One forecaster advised people to avoid the beach entirely this weekend. And organizers of the King memorial dedication said that the ceremony could be moved from morning to afternoon if the weather is too bad.

Forecasters said they expected the worst Saturday night, as the storm center passes off the Virginia capes, with gradually improving conditions in the Washington area Sunday.

By noon Sunday, Irene is expected to be off Atlantic City and accelerating north into cooler water.

But the storm could leave lingering rain bands and blustery wind in its wake, as tens of thousands of people, including President Obama, assemble for the 11 a.m. memorial dedication on the Tidal Basin.

Organizers said the ceremony will be held rain or shine, but the project’s executive architect, Ed Jackson Jr., said it could be pushed back if necessary.

“Right now, everything remains according to the current plan,” he said. “With the passing of the hurricane, if it goes up the East Coast, what we would simply do is delay the actual dedication to the afternoon, as opposed to the morning hour, allowing the rain from the hurricane to move north.”

He said it was too soon to know when such a call would be made. “This is just one possible scenario,” he said. “We don’t know the severity of what we’re faced with at this point.”

The five days of dedication ceremonies had already disrupted by the earthquake. Organizers have moved Wednesday’s gala kickoff dinner out of the National Building Museum and shifted Saturday’s interfaith service from the Washington National Cathedral because both structures were damaged.

The dinner, scheduled to feature former U.S. Secretary of State Madeleine Albright, was moved to the Washington Convention Center. The 3,000-person interfaith service was moved to the Basilica of the National Shrine.

The hurricane, a Category 3 storm, was in the Bahamas and heading northwest Wednesday, with sustained winds of well over 100 mph.

The National Hurricane Center expected the storm to intensify and reach Category 4 strength, with winds of more than 130 mph, by Thursday.

It was then forecast to turn north, then northeast, brushing past North Carolina’s Outer Banks and accelerating toward New Jersey and New England, then gradually weakening.

Evacuations were underway along the North Carolina coast Wednesday.

“They’re going to be experiencing hurricane-force gusts to 80 mph in, like, Morehead City,” said Paul Walker, a senior meteorologist with AccuWeather, a private weather forecasting agency. “Hatteras could have a major hurricane if this thing stays on its current track, [with] wind gusts of 125 mph.”

Andy Woodcock, a meteorologist with the National Weather Service in Sterling, said, “This is a pretty big storm right now.”

In the Washington area, wind should not be a significant issue, Woodcock said. “There are not going to be any 90 mph winds. Thirty to 40 is a possibility.”

Rain could be the problem.

“Tropical storms, precipitation-wise, they’re just different animals,” he said. “You can just get so much rain so quickly.”

The area could get 3 to 5 inches of rain Saturday, he said, which could drench outdoor events such as a King memorial march headed by the Rev. Al Sharpton.

Sunday could start out stormy but then clear as the day progresses, with a stiff wind, Woodcock said. He said there was an 80 percent chance of showers and thunderstorms Saturday night and a 20 percent chance Sunday.

But he said Sunday could also see scattered rain bands from Irene. “With those, it can go from not raining to a downpour in a minute and a half,” he said. “If the storm should slow down, that could complicate things further.”

As for the beaches, Woodcock urged vacationers to stay away this weekend. “The waters will be unswimmable,” he said. “The rip currents will be so strong. . . . It’s just going to be so dangerous. Waves could be 10, 12 feet high.”

“This just is not the weekend to go to the beach,” he said.