Atlantic Canadians are bracing for the worst as officials warn tropical storm Leslie is "racing toward Newfoundland," and its effects are expected to be felt throughout the region.

"The centre of Leslie is forecast to move over eastern Newfoundland on Tuesday morning," the US National Hurricane Center said Monday afternoon, adding a hurricane watch was in effect from Stone's Cove to Charlottetown and a tropical storm warning was in effect from Indian Harbour to Triton.

The storm had already dumped heavy rains on Nova Scotia and parts of Newfoundland by then, prompting the closure of some public buildings and several roads due to flooding.

The two provinces, along with Prince Edward Island, remain under a rainfall warning.

Meanwhile, winds were expected to start whipping the area beginning Monday night, some of the strongest expected over eastern Newfoundland and Cape Breton Tuesday morning.

The US agency reported winds were reaching 95 km/h, with gusts up to 120 km/h.

The threat of surging coastal waters prompted Marine Atlantic to cancel ferry service between Newfoundland and Nova Scotia. until at least Wednesday, and two cruise ships cancelled its stops at St. John's.

The government of Newfoundland activated a special hurricane information link on its home page and warned citizens to be prepared for flooding and power outages.

Residents should be ready to be on their own for a couple of days if Leslie hits hard, said Dan Bedell, a spokesman for the Red Cross in Atlantic Canada.

"In the initial hours after a severe storm, emergency officials need time to assess the damage and set priorities and determine who needs help the most and focus on that," he said. "That's why we caution everyone they need to be able to look after themselves for a few days."

When Hurricane Igor hit Newfoundland in 2010, many people were trapped in their homes, or even in their isolated communities, because of flash flooding and other obstructions on the roads.

Leslie's effects will be "far-reaching with a circulation about 800 kilometres in diameter," the Canadian Hurricane Centre said.

Officials advise having a portable radio with fresh batteries, as well as a charged cellphone at the ready and a car charger to top it up because a cordless phone doesn't work when power is out.

It's important not to lose all contact with the outside world, Bedell said.

The National Hurricane Center said the storm was not expected to get stronger before it reached eastern Canada, but it was "racing" toward Newfoundland at a speed of about 41 km/h.