Tropical storm Arthur, the first named storm of the 2014 Atlantic hurricane season, has almost strengthened into a hurricane, the U.S. National Hurricane Center said in its latest advisory on Wednesday.

The storm was located about 355 kilometres south-southeast of Charleston, South Carolina, with maximum sustained winds of 113 km/h, the Miami-based weather forecasters said.

A hurricane warning has been issued for parts of the North Carolina coast, it added. 

CBC News meteorologist Ian Black said much could change by the weekend, but if Arthur continues to strengthen, Nova Scotia could be in for a “direct hit” from a Category 1 hurricane.

Along much of the U.S. East Coast, hotel owners, tourism officials and would-be vacationers kept a watchful eye on forecasts the forecast to see if the storm would interrupt Fourth of July plans.

Weather models predict Arthur will skim the Outer Banks, a string of narrow barrier islands prone to flooding but popular for beachgoers, as a Category 1 hurricane Friday.

Wednesday's warning stretched across the entire North Carolina coast, from Little River Inlet near South Carolina north to the Virginia border.

A tropical storm watch for Florida's east coast was cancelled.

The annual Boston Pops July 4th outdoor concert and fireworks show, one of the city's signature events that’s attended by hundreds of thousands, is being moved up a day because of potential heavy rain ahead of Tropical Storm Arthur.

The celebration is being rescheduled to what appears to be the better of two potential bad weather days, organizers and public safety officials said Wednesday afternoon.

"It's not optimal. We wish it were, but we've got to deal with this," state police Col. Timothy Alben said.

Final destination: Atlantic Canada

Environment Canada said Wednesday that Arthur could play a role in Atlantic Canada's weather this weekend. 

"At this point the likelihood is for an offshore track which would lead to a primarily 'rain event' over land," the weather agency said on its website. "However, it really is too early to rule out a direct impact."

CBC meteorologist Jay Scotland said it appears Arthur will cross Nova Scotia on Saturday  and could potentially reach Newfoundland on Sunday, though he cautioned the forecast of the storm's track will likely change over the next few days.

The Canadian Hurricane Centre will release a full forecast later today.

Although the storm's track is uncertain, the Stan Rogers Folk Festival in Canso, N.S., announced it was cancelling the event that was scheduled to begin Friday and continue through the weekend.

Festival artistic director Troy Greencorn says the decision was made because of public safety concerns.

North Carolina expected to get worst of Arthur

The worst of the storm should occur at Cape Hatteras, N.C., about dawn Friday, with 70 to 130 millimetres of rain and sustained winds up to 137 km/h, said Tony Saavedra, a meteorologist at the U.S. National Weather Service. The storm should move through quickly and be off the coast of New England later in the day.

Tropical Weather storm Hurricane Arthur U.S.

With the July Fourth weekend on the horizon, the Atlantic hurricane season's first named storm plodded off Florida's coast but wasn't yet spooking too many in the storm's potential path. (Jim Tiller/The Daytona Beach News-Journal/AP)

The motel Shutters on the Banks in Kill Devil Hills, N.C., was completely booked for the holiday weekend, general manager John Zeller said Tuesday, but he was considering waiving cancellation fees if the storm continued to track toward the area.

"We have received some cancellations but not too many," he said. "Basically we are telling people to kind of wait and see what happens. ... I think everybody is kind of watching the weather."

Business as usual

About an hour north of Cape Canaveral, the Hilton Daytona Beach Oceanfront Resort's holiday reservations were unaffected by the storm, general manager Tom Manno said.

"In fact we're sold out right through Sunday," he said. "So we haven't experienced any cancellations at all."

But some precautions were taken at the hotel.

Tropical Weather

Lifeguard Travis Blakeslee raises the red high-hazard flag at a Red Cross lifeguard station in Jacksonville Beach, Fla. The flag was raised in anticipation of rip currents and high waves from tropical storm Arthur. (Will Dickey/The Florida Times-Union/AP)

"We've gone through all the emergency procedures, the staff is confident, and everything is in place," Manno said. "Right now the weather is good, the winds are pretty calm, and we're hoping it will remain that way."

On Florida's Gulf Coast, the National Weather Service says dry air rotating around Arthur reduced rain chances in the Tampa Bay area. But as the storm moves north, the rain chances will return — just in time for the holiday weekend.

On Hilton Head Island, on South Carolina's southern tip, there was little concern about Arthur — the storm was forecast to pass the island on Thursday well out at sea.

"It's a very busy week on Hilton Head Island ... It will be a sold-out weekend," said Charlie Clark, a spokeswoman for the Hilton Head Island Chamber of Commerce. "We're expecting a strong weekend and we're not getting calls from visitors asking what's up with this.

With files from CBC News, The Canadian Press and Reuters