A storm headed towards the Maritimes is expected to lose its hurricane strength when it arrives in the region Saturday, but still carry potent winds and heavy rains.
Meteorologist Bob Robichaud of the Canadian Hurricane Centre said Thursday he expects Arthur to be a strong post-tropical storm with sustained winds of 65 kilometres an hour or more.
It was classified as hurricane earlier Thursday in the United States, where it was likely to reach Category 2 status. That means a minimum wind speed of 154 km/h, while a Category 1 storm is 119 km/h.
But Robichaud said that even with the expected weakening of the system as it moves north, it could pack strong winds when it arrives late Friday or early Saturday morning.
"We're still looking right now at a tropical storm arriving, but very, very close to hurricane strength," he said.
"So yes, this is something we're watching quite closely."
Robichaud expects Nova Scotia will experience the heaviest winds while New Brunswick could see the most rainfall, adding that it's still too early to determine where Arthur could make landfall.
Forecasters are watching to see how the storm interacts with a trough of low pressure that could indicate how much rain it will bring, but say up to 100 millimetres could fall in parts of New Brunswick.
"In terms of the worst wind, it looks like Nova Scotia and in terms of the worst rain it looks like New Brunswick," said Robichaud.
He said the hurricane centre will have a better handle on potential storm surge Friday afternoon, but cautions that there could be higher water levels along the Atlantic coast and the Northumberland Strait.
Arthur threatened to give North Carolina a glancing blow on Friday, prompting thousands of vacationers and residents celebrating Independence Day to leave parts of the state's popular but flood-prone Outer Banks. Much of the North Carolina coast was under a hurricane warning as the National Hurricane Center in the U.S. predicted Arthur would bring winds or up to 136 km/h to the state's coastline.
Farther north in Boston, one of America's signature Fourth of July events, the annual Boston Pops outdoor concert and fireworks show, was moved up a day because of potential heavy rain ahead of the hurricane.
Arthur, the first named storm of the Atlantic season, prompted a hurricane warning for much of the North Carolina coast. Tropical storm warnings were in effect for coastal areas in South Carolina and Virginia.