Tropical storm Rafael is expected to reach hurricane strength in the Atlantic later Monday and by mid-week will bring rain to Atlantic Canada.
As of early Monday, the storm was 450 kilometres north of San Juan, Puerto Rico and had winds of 110 km/h as it moved north-northwest at 17 km/h.
Sustained winds were approaching hurricane status (119 km/h) and Rafael will likely be upgraded to a Category One storm during the day, forecasters said.
The Leeward Islands of the Lesser Antilles will get heavy rain Monday, while tropical storm force winds will lash Bermuda on Tuesday.
The U.S. National Hurricane Center said the storm is not expected to make landfall in Newfoundland.
Elsewhere, Hurricane Paul has formed in the Pacific off Mexico's coast and a tropical storm watch has been issued for a portion of Baja California.
Paul's maximum sustained winds early Monday were nearing 120 km/h. Some additional strengthening is forecast during the day but the U.S. National Hurricane Center says weakening is expected to begin by Tuesday.
The hurricane was centred about 910 kilometres southwest of the southern tip of the Baja California peninsula and was moving north at 11 km/h.