Between 50 and 70 millimetres of rain is expected to fall starting Sunday evening across the southern half of Nova Scotia, Cape Breton Island and much of Newfoundland.
"Localized flooding in low-lying areas is possible," according to Environment Canada. "Watch for possible washouts near rivers, creeks and culverts."
Halifax County east of Porters Lake, Guysborough County and Cape Breton are also under wind warnings and are expected to receive strong southerly winds with gusts up to 90 km/h that are expected to diminish around 12 p.m. AT Monday.
"Damage to buildings, such as to roof shingles and windows, may occur. Loose objects may be tossed by the wind and cause injury or damage. Be prepared to adjust your driving with changing road conditions due to high winds. Avoid wooded areas to prevent injury from falling trees or branches. Campers should move to sturdy shelters," Environment Canada said.
The coastal parts of Newfoundland are expected to be hit with high winds developing this evening out of the south.
Powerful wind gusts for much of the island are expected to reach as high as 120 km/h Sunday and increase to up to 140 km/h Monday morning. The southerly winds are expected to shift to more southwesterly winds Monday afternoon, tapering off.
Wind warnings are issued when there is a significant risk of damaging winds, the weather service said.
A special weather statement has been issued for parts of central and eastern Labrador as well, where 30 to 40 millimetres of precipitation is expected throughout the day Monday.