A satellite image taken Sunday afternoon shows Hurricane Danielle, located northeast of Bermuda. To the south, Hurricane Earl is shown east of Antigua.
Hurricane Earl strengthened as it began buffeting the Northern Leeward islands in the Caribbean on Monday and was seen becoming a powerful storm within the next 24 hours, the U.S. National Hurricane Center said.
Earl carried sustained winds of 105 miles per hour (169 kph) and was a Category 2 hurricane in the five-step Saffir-Simpson scale of intensity.
"Hurricane conditions are now spreading into the Northern Leeward Islands and will spread westward into the Virgin Islands later today," the hurricane center said in its 5 a.m. (0900 GMT) advisory.
"Earl is expected to become a major hurricane by tonight or early Tuesday," it added.
The storm's center was 50 miles (80 km) east-northeast of the French overseas island of St. Martin and moving north-northwest.
Hurricane warnings were in effect through the Caribbean, including the U.S. and British Virgin Islands, Antigua and Barbuda and the British overseas territories of Anguilla and Montserrat.
Tropical storm conditions were likely to spread over the U.S. territory of Puerto Rico on Monday, with hurricane conditions possible by evening.
The hurricane center warned of a storm surge, dangerous waves and heavy rains that could cause flash flooding and mudslides in areas of higher elevation.
Caribbean airline LIAT canceled 41 flights to several destinations in the eastern Caribbean and shut down its reservation service because of Earl's approach, according to a company statement.
Forecasters said Earl might affect the U.S. East Coast later this week.
In the North Atlantic, Hurricane Danielle, a major Category 4 storm last week, was barely a hurricane on Monday morning as its sustained winds fell to 75 mph (121 kph). The storm was expected to lose its tropical characteristics later in the day.
It was about 440 miles (708 km) south of Newfoundland.
Earl carried sustained winds of 105 miles per hour (169 kph) and was a Category 2 hurricane in the five-step Saffir-Simpson scale of intensity.
"Hurricane conditions are now spreading into the Northern Leeward Islands and will spread westward into the Virgin Islands later today," the hurricane center said in its 5 a.m. (0900 GMT) advisory.
"Earl is expected to become a major hurricane by tonight or early Tuesday," it added.
The storm's center was 50 miles (80 km) east-northeast of the French overseas island of St. Martin and moving north-northwest.
Hurricane warnings were in effect through the Caribbean, including the U.S. and British Virgin Islands, Antigua and Barbuda and the British overseas territories of Anguilla and Montserrat.
Tropical storm conditions were likely to spread over the U.S. territory of Puerto Rico on Monday, with hurricane conditions possible by evening.
The hurricane center warned of a storm surge, dangerous waves and heavy rains that could cause flash flooding and mudslides in areas of higher elevation.
Caribbean airline LIAT canceled 41 flights to several destinations in the eastern Caribbean and shut down its reservation service because of Earl's approach, according to a company statement.
Forecasters said Earl might affect the U.S. East Coast later this week.
In the North Atlantic, Hurricane Danielle, a major Category 4 storm last week, was barely a hurricane on Monday morning as its sustained winds fell to 75 mph (121 kph). The storm was expected to lose its tropical characteristics later in the day.
It was about 440 miles (708 km) south of Newfoundland.