A satellite image taken early Friday shows tropical storm Danny east of the Bahamas. (Weather Underground/Associated Press)

Tropical storm Danny has further weakened in the Atlantic Ocean and is not expected to pose a hurricane threat to Canada's East Coast when it tracks past on the weekend, according to forecasters.

Danny has weakened to the point that it is "barely a tropical storm," forecasters with the U.S. National Hurricane Center said Friday.

However, a tropical storm watch remained in effect for North Carolina as large swells created by the storm produced dangerous surf and rip currents on the coast. A 12-year-old boy went missing while body-boarding. His mother said she saw him go under the water near the town of Corolla, N.C.

A U.S. Coast Guard spokesman said waves were 1.2 metres to 1.8 metres. The search was called off at 9 p.m. ET.

The dangerous conditions are expected to continue for at least 48 hours as the storm passes near the coast of North Carolina overnight before reaching the coast of New England late Saturday, according to the U.S. hurricane centre.

Danny's maximum sustained winds were about 65 km/h by about 11 p.m. ET Friday morning.

Danny is the fourth named Atlantic storm of the 2009 hurricane season.

The centre of the storm was about 425 kilometres south of Cape Hatteras, N.C., moving on a northwest track at about 19 km/h.

"Danny is expected to remain below hurricane strength," the Canadian Hurricane Centre said Friday.

The Canadian centre said the storm will likely weaken further as it moves through Canadian waters. But marine gale warnings may be posted for some parts of the Maritimes, the centre said.

Bob Robichaud, a meteorologist with the Canadian Hurricane Centre, said in an interview that people in the Maritimes can expect the storm to bring a lot of rain over the weekend.

"Oftentimes, when these things come up our way, there is a thin band of rain that comes up ahead of the storm," he said.

"So that is kind of what we're going to be seeing tomorrow and then the rain will get heavier Saturday evening into Saturday night and I think by Sunday morning most of the rain associated with whatever is left of Danny should be well east of the Maritimes."

Almost 70 mm of rain could fall in southwest Nova Scotia and southern New Brunswick, with the possibility of 90 mm or higher possible locally, the hurricane centre said, adding that portions of Newfoundland could get 50 mm of rain.

Similar path

The Canadian Hurricane Centre indicates Danny will likely take a similar path to Hurricane Bill, which reached Atlantic Canada last weekend.

Friday's forecast shows Danny tracking along the spine of Nova Scotia and later moving eastward across central Newfoundland. There is also the possibility that the weather may affect southern Nova Scotia and central New Brunswick.

Although the storm had weakened, there remains a slight possibility it will regain strength Friday, the U.S. hurricane centre said.

Hurricane Bill hit Nova Scotia last Sunday with high winds, heavy rain and dangerous surf. The storm knocked out power to thousands of Nova Scotia homes and businesses.

Bill reached Newfoundland later that day, blasting the province's south coast with winds of 70 km/h and gusts to 100 km/h.