Julia joins Hurricane Igor, which weakened early Tuesday, but still maintained its status as a powerful Category 4 storm as it churned far from land.
At 5 a.m. ET, Igor had top sustained winds of 135 mph (215 kph) and was moving to the west-northwest at 8 mph (13 kph), according to forecasters. The storm's center was about 750 miles (1,205 km) east of the northern Leeward Islands. Igor, which started as a tropical storm on Saturday, rapidly intensified from a Category 2 to a Category 4 storm Sunday.
"Some fluctuations in intensity are possible during the next couple of days, but Igor is expected to remain a dangerous hurricane through Wednesday," the center said, but added it would likely drop to a Category 3 storm by the end of the week.
Hurricane-force winds extended up to 50 miles (85 km) from Igor's center, and tropical storm-force winds could be felt up to 195 miles (315 km) outward, according to the center.
While the storm is expected to stay north of the Caribbean islands, the islands are expected to experience dangerous surf conditions, along with some wind and rain because of Igor's size, forecasters said.
Meanwhile, in the far eastern Atlantic, Julia kept pace, becoming the fifth hurricane of the Atlantic season.