(CNN) -

Arthur was holding steady as a tropical storm, not quite rising to the hurricane moniker Wednesday night. But it is poised to cause some holiday travel havoc.

At 11 p.m. Wednesday, its maximum sustained winds were 70 mph, 3 mph shy of the hurricane category, the National Weather Service said.

Arthur, the first named storm of the Atlantic tropical cyclone season, is churning up the East Coast and might be at its most dangerous Thursday as it grinds up against the North Carolina coast.

So far, that is the only part of the country predicted to be hit with hurricane force winds, but the weather system also is causing problems farther north. Officials said Wednesday afternoon that the annual Boston Pops Fireworks Spectacular, normally held on July 4, will be moved to Thursday because of the potential for bad weather.

Arthur is expected to become a Category 1 hurricane off the North Carolina coast on Thursday, and although the eye might not hit land, the storm could create dangerous rip currents that day along the Outer Banks and Pamlico Sound, forecasters said.

North Carolina's governor issued a tropical storm warning for the entire coast and sent this message to those who plan to hit the beaches: Stay out of the ocean.

"I don't want you to put at risk not only yourself but also people who may try to help you, especially our emergency operation workers," said Gov. Pat McCrory.

"Don't put your stupid hat on," McCrory said at the New Hanover County Emergency Operations Center, according to CNN affiliate WWAY.

Late Wednesday, a mandatory evacuation order was issued for Hatteras Island and a voluntary evacuation order went out to Ocracoke Island.

Some vacationers at Southern Shores, North Carolina, said they weren't too worried.

"We've been coming down here for 20 years," said Jim Stafford of Greenville, Pennsylvania, as he stood in front of the beachfront house where he's staying. "We'll just see what happens."

When asked whether he was taking any precautions, Stafford said he planned to fill up the gas tank on his car "just in case."

Strong winds could push water to the point where the underwater sandbars in front of North Carolina's beaches break, creating rip currents that would rush swimmers out to sea, CNN meteorologist Chad Myers said.

"There's no time for you to react. That's why you can't be there at all," Myers said, describing a danger area from Wilmington north to Nags Head.

"This is not a landfall-problem hurricane. This is a rip-current-problem hurricane," he added.

As for Independence Day, the storm could send rain to the Washington area during the day, but forecasters said it shouldn't spoil most of Friday night's festivities -- including a colossal fireworks show on Washington's National Mall -- as it veers away from land. PBS is planning to broadcast the pyrotechnics blossoming over the Reflecting Pool live via 20 cameras.

Those wet roads

In Boston, officials said there's a chance of rain Thursday, so the city's music-and-fireworks event might not happen that day either, reported CNN affiliate WCVB.

The fireworks could be rescheduled but not the concert by the Boston Pops, State Police Col. Timothy Alben said, according to WCVB.

"The rain is a factor for the orchestra," event organizer Rich MacDonald told the television station. "If the rain is coming down hard enough that it is coming down into the Hatch Shell then it affects the instruments and these instruments are valuable and old."