(Reuters) - Hurricane Irma is moving very close to the northern Leeward Islands and the category 5 storm is expected to move over sections of the Caribbean islands by Tuesday night or early Wednesday, the U.S. National Hurricane Center (NHC) said. The  potentially catastrophic  hurricane was about 50 miles (75 km) east-southeast of Barbuda, with maximum sustained winds of 185 miles per hour (295 kph), the NHC said. 