With the forecast calling for heavy rain, Halifax municipal workers are out clearing debris from drains and storm pipes.
Up to 100 millimetres of rain could fall on much of Nova Scotia by Friday evening.
CBC meteorologist Peter Coade said a trough of low pressure is moving in from the west as tropical storm Sean moves north from Bermuda.
"The moisture from it is moving northward, so it's coming in line with the trough moving in from the west and between the two of them giving us all this rain," he said Thursday.
Coade said people in areas prone to flooding should prepare for the rain.
Halifax Water says municipal crews are out clearing leaves and other debris from catch basins. The water commission urges homeowners to do the same.
The Remembrance Day ceremony in Grand Parade is expected to go ahead as scheduled, though organizers say it will be shortened to 30 minutes if the weather is particularly bad.
But ceremonies in Sackville, Clayton Park and in Bedford will move inside.
The Bedford event change was a difficult decision for Legion Branch #95.
"We decided in the end, and it was a collaborative decision of the executive, to move it in the best interests of everyone involved," Garry White, president of the Legion.
But another big ceremony, the Dartmouth event at Sullivan's Pond, will stay outdoors.
"All our veterans when they were overseas, they never went inside when it was raining and we don't intend to do it tomorrow. We will march off," said Wayne Masters, of the Royal Canadian Legion Somme Branch 31.
Many other Legions around the province, including Truro and Bridgewater, have decided to move their events indoors.
Coade said Sean could become a hurricane but is not expected to threaten Nova Scotia.