Parks Canada will close several Nova Scotia parks and historical sites this weekend due to the impending arrival of Hurricane Earl.

Kejimkujik National Park, Kejimkujik Seaside, the Fort Anne National Historic Site and the Port Royal National Historic Site will all close Friday. Parks Canada will reassess the closures Saturday.

The Canadian Hurricane Centre has issued a hurricane watch for four Nova Scotia counties and expanded its tropical storm watch to include large sections of Nova Scotia and New Brunswick.

Hurricane Earl is moving up the Atlantic and expected to hit the Maritimes Saturday.

In Nova Scotia, the hurricane watch affects Queens County, Shelburne County, Yarmouth County, and Digby County. The tropical storm watch is for everywhere else in Nova Scotia except the northern mainland and Cape Breton.

In New Brunswick, a tropical storm watch is in effect for Saint John and its surrounding county, Grand Manan island and coastal Charlotte County, the city of Moncton and southeast New Brunswick, including Fundy National Park.

Environment Canada's 9 p.m. forecast said Earl had weakened to a strong Category 2 hurricane. It may release additional watches and warnings overnight Thursday.

Chris Fogarty, program supervisor for the Canadian Hurricane Centre, said Earl is expected to arrive early Saturday either in western Nova Scotia or along New Brunswick's Fundy Coast.

Fogarty said during a news conference Thursday afternoon that there's about a 60 per cent chance Earl will make landfall with at least hurricane-force gusts. The hurricane threshold is 119 km/h.

The chance of hurricane winds in P.E.I. is about 20 per cent.

Storm windiest on its east side

The latest forecast shows Earl essentially entering the mouth of the Bay of Fundy, possibly making landfall at Digby County in Nova Scotia or Grand Manan Island in New Brunswick.

Being in the centre of the track does not mean being hit with the worst conditions. Winds will be strongest on the eastern side of the storm, which on that track would mean the strongest winds for western Nova Scotia, southeastern New Brunswick and most of Prince Edward Island.

Fogarty said New Brunswick would likely see more rain than Nova Scotia, but since Earl is moving quickly, rainfall amounts are likely to be kept down. Two or three hours of intense rain would be expected, he said, totalling 40 to 70 mm.

And if Earl lands in New Brunswick, he added, the probability it would still be a hurricane by then is lower. The storm would lose strength as it moves over the cooler waters of the Bay of Fundy, he said.

Regardless, Environment Canada says it is "very likely" the Maritimes will be hit with high winds and heavy rains on Saturday.

Forecasters say there's about a 90 per cent chance that Nova Scotia and Prince Edward Island will be hit with at least gale-force winds of 60-70 km/h. The chances for New Brunswick are at about 70 per cent.

Gale warnings are in effect for Browns Bank and Georges Bank, and the weather office said it's very likely that further warnings will be issued in Maritime waters, starting at 3 a.m. Friday.

Sea swells from Earl are expected to reach the Nova Scotia coast Thursday night.

High waves and pounding surf are expected along the southern Maritime coasts Friday night and along the Gulf of St. Lawrence coastlines Saturday afternoon and evening.

Getting ready

As a precaution, natural gas company EnCana is evacuating 88 non-essential workers from a rig off Nova Scotia. Two vessels are being moved out of Earl's projected path.

Bay Ferries Inc. has cancelled Saturday crossings of the Princess of Acadia ferry between Saint John and Digby, N.S., said company representative Danny Bartlett.

No decision has been made about the ferry between Wood Islands, P.E.I., and Caribou, N.S., though an official said there's a "strong possibility" it could be cancelled.

So far, the Port of Halifax will be one cruise ship short.

"At this point was have one cruise ship that has decided to go to Boston instead of Atlantic Canada this weekend and we have one that's coming a day early," said Michele Peveril, a port authority spokeswoman.

Acadia University in Wolfville has pushed back its Welcome Week activities a day to Sunday, so students and parents don't have to travel in the height of the storm.

The Nova Scotia Department of Natural Resources said it will decide on potential park closures as the storm gets closer.

In New Brunswick, Andy Morton of the Emergency Measures Organization warned that Maritimers should gas up their vehicles and make sure they have milk and food on hand.

"I'm not saying go out and buy 40 days of food and stock the house with it," he said. "But everybody should be prepared to get by on their own for at least 72 hours."

Hurricane Earl was approaching North Carolina on Thursday. The powerful storm was packing maximum sustained winds of 204 km/h and moving north at 30 km/h.