SAINT JOHN, N.B. -- Parts of the rain-soaked Atlantic region are bracing for another deluge from a massive, slow-moving storm that could cause flooding in southwestern New Brunswick.

"The impacts are going to be greater because the ... conditions are already primed for flooding," meteorologist Linda Libby said her Environment Canada office in Charlottetown.

"(They're) looking at getting 75 to 100 millimetres of rain falling in that area, and it may even possibly extend into the very western portion of Nova Scotia."

Libby said the "meandering" storm is expected to hang around longer than usual, which means some areas could get drenched over and over again.

Robert Duguay, spokesman for the New Brunswick Emergency Measures Organization, said people should prepare to take care of themselves for up to 72 hours.

The organization is recommending people stock up on food, water, medication, batteries and other necessities, as there is an increased risk of power outages.

Duguay said driving conditions are expected to be hazardous, and he warned that motorists should watch for wildlife fleeing flooded areas.

"At this point, the St John river basin is at full capacity," he said, adding that some roads have already been closed. "We're diligently working today with local authorities in regions to make sure we look at every possibility."

He said people who live close to the St John river should consider moving belongings to higher ground.

"We are trying to plan for everything because it can happen anywhere, depending on the storm."

Environment Canada issued rainfall warnings for New Brunswick, and another burst of rain is forecast in southern New Brunswick on Monday.

Meanwhile, western Nova Scotia can expect to see about 50 millimetres of rain over the weekend.

As the storm moves northward, residents of Labrador should expect around 25 mm, starting later in the weekend, said Libby.

The nasty weather system has already caused extensive flooding in Ontario and Quebec.

The problem is particularly acute in Quebec, where 132 communities have been affected by flooding. Some 700 people have been forced to abandon their homes.

Environment Canada is calling for an additional 30 millimetres of rain north of the St. Lawrence River, adding Montreal may experience a slightly lesser amount. Eastern Quebec was also beginning to experience flooding due to the rain and melting snow.