The Canadian Hurricane Centre in Halifax says Bertha has weakened to a tropical storm as it continues to move in a northeasterly direction.
The storm, located about 731 kilometres west-northwest of Bermuda, has maximum sustained winds of 102 kilometres an hour.
Forecasters say the storm will gradually weaken over the next 24 to 30 hours and will pass well south of Nova Scotia.
However, it is expected to interact with an approaching trough from the west on Wednesday.
Forecasters say that interaction as the storm approaches the Grand Banks, could see Bertha track closer to Newfoundland on Thursday.