HALIFAX -- Environment Canada is warning residents of the Maritimes to brace for a tropical storm later this week, saying heavy rain and gusty winds could cause minor damage and isolated power outages.

Tropical storm Erin was expected to form late Tuesday or early Wednesday off the Carolinas as the tropical depression gained strength while moving northeastward toward Nova Scotia.

The storm was forecast to approach the province's Atlantic coast by Friday morning.

A storm tracking map produced by the Canadian Hurricane Centre in Halifax indicated Erin's maximum sustained winds could reach 75 kilometres per hour as it approaches Nova Scotia, but the storm would still be well offshore.

Still, the forecast is calling for up to 100 millimetres of rain in some parts of the Maritimes.

As of late Tuesday afternoon, the storm was more than 500 kilometres southeast of Cape Hatteras, N.C., churning out maximum sustained winds at 56 kilometres per hour.

The storm's wind speed was expected to increase as it heads north along the eastern seaboard.

However, with the storm still 1,500 kilometres from Canadian territory, the Canadian Hurricane Centre said it could provide only a generalized forecast, as the track of the storm could change.

The latest prediction for its route had the storm travelling toward Nova Scotia before moving over Newfoundland Friday night.

"It could still be strong enough to cause isolated power outages and minor damage, especially given that trees are still in full leaf," Environment Canada said in a tropical cyclone information statement.

"Details will become more clear in the coming days as the system becomes better defined and draws nearer to our region .... Gale warnings will likely be required for waters near and adjacent to the track Erin takes through our region later on Thursday and Friday."

Environment Canada says a significant storm surge is unlikely, though higher-than-normal water levels and rough surf are possible to the right of the storm's track.