Hurricane Dorian will sideswipe the Cape and Islands with heavy rain, strong winds, and high seas late Friday into early Saturday morning, as the Category 1 storm moves swiftly up the Eastern Seaboard, passing southeast of Nantucket.

A tropical storm warning has been issued for Cape Cod, the Islands, and adjacent waters as of Friday morning, according to the National Weather Service.

The hurricane will be well off the coast and much weaker than when it devastated the Bahamas in recent days and pounded the coast of the Southeastern United States.

The Oak Bluffs ferry terminal on Martha’s Vineyard was ordered closed Friday before noon, with trips diverted to Vineyard Haven due to weather conditions, the Steamship Authority said in a tweet.


The agency said Nantucket service for the weekend is on hold as is Martha’s Vineyard service until 1:35 p.m. Saturday, citing winds blowing 40 to 60 miles per hour and waves as high as 11 feet.

The heaviest rainfall is expected to arrive in Massachusetts at around 8 p.m. Friday, according to the weather service

The Cape and the Islands could see 2 to 4 inches of rain, bringing minor poor drainage flooding, primarily to roads.

To the northwest of the Cape Cod Canal 1 to 1.5 inches are expected. In Western Massachusetts, 0.5 to 0.75 inches could fall, the National Weather Service office in Norton said in an Internet posting.

Dorian will be in its closest proximity to the Cape and Islands during the predawn hours on Saturday, said Nicole Belk, a meteorologist with the National Weather Service.

The strongest winds will be felt from 6 a.m. to noon Saturday, with 45 to 55 mile per hour gusts in the Cape and Islands, Belk said. Nantucket is expected to see the worst winds, with a possibility of 60 mile per hour gusts, the posting said.


Peak wind gusts in Plymouth could reach 40 miles per hour and the Boston area may experience 30 to 35 mile per hour wind gusts.

The storm will whip up seas, possibly causing minor coastal flooding for Nantucket Harbor at high tide on Saturday morning.

Chatham Harbormaster Stuart Smith said his crew was continuing to secure boats and check mooring lines.

Only 100 boats had been removed from the water in Chatham, with over 2,400 remaining as of Friday afternoon. Most people are betting on nicer boating weather come Sunday, he said.

“There’s still a lot of boating in September and October, and for some these boats are just too big to get out quickly. People will probably go boating on Sunday, but we are cautioning them that it will likely be rough.”

Plymouth Harbormaster Chad Hunter said extra staff had been added on Friday night into Saturday morning to walk the pier and keep an eye out if boats come loose because of the storm.

“We’re kind of out on the fringe, right on the edge here,” Hunter said.

Hunter’s staff were checking lines, adding lines, and tying down anything that might come loose from the storm.

Fortunately, he said, most boats, about 500 to 550, had already been removed from the harbor.

Late-season ocean swimmers and big-wave spectators should beware, forecasters said.

High surf is expected along south-facing ocean beaches Friday and along both the south- and east-facing beaches on Saturday. Dangerous rip currrents are possible that “can rapidly carry a swimmer into deeper water and exhaust an individual trying to swim against it,” forecasters warned.


The forecasters also said, “Viewers of large surf should stay in safe areas well away from possible splashover. Individual waves may be more than twice the average wave height, which can sweep a person into the water from whta may seem to be a safe viewing area,” the forecasters said in a high surf advistory.

Martin Finucane of the Globe staff contributed to this report. Jordan Frias can be reached at jordan.frias@globe.com.