Rafael reached hurricane strength late Monday south of Bermuda with top sustained winds of 140 kilometres an hour.
It is forecast to pass just east of Bermuda today.
The Canadian Hurricane Centre in Halifax says Rafael is expected to lose some steam as it moves north over cooler waters, though its winds could still pack a punch out at sea around the Grand Banks off Newfoundland.
The storm is expected to pass south of or over the Grand Banks late Wednesday or early Thursday.
The centre says Newfoundland's Avalon Peninsula could see heavy rainfall Wednesday depending on how Rafael interacts with a trough of low pressure in the area.