(Updates with storm's location, details)
MIAMI, July 26 Tropical Storm Dorian weakened on Friday as it moved across the open waters of the Atlantic Ocean toward the Caribbean, the U.S. National Hurricane Center said.
Dorian, the fourth named storm of the 2013 Atlantic hurricane season, was centered about 1,135 miles (1,830 km) east of the Northern Leeward Islands and was moving west-northwest at 22 miles per hour (35 km per hour). It had top sustained winds of 45 mph (72 kph), the hurricane center said.
Dorian posed no immediate threat to the Gulf of Mexico, where U.S. oil and gas operations are clustered.
The storm is becoming less organized and is forecast to be downgraded to a tropical depression on Sunday, the center said. Computers models show Dorian will then continue to move west as a mass of thunderstorms and pass north of Puerto Rico on Monday. (Reporting by Kevin Gray; Editing by Leslie Adler and Eric Beech)