(Reuters) - Irma, now a category 4 , is heading towards the Leeward Islands in the Caribbean and is expected to move near or over the northern part of the region by Tuesday night or Wednesday, the U.S. National Hurricane Center said. Hurricane Irma is about 320 miles (515 km) east of the Leeward Islands and packing maximum sustained winds of 150 mph(240 km/h), the Miami-based weather forecaster said.   Swells generated by Irma will affect the northern Leeward Islands, Puerto Rico, and the U.S. and British Virgin Islands during the next several days,  the NHC said.  
Dangerous hurricane Irma moving towards Caribbean islands: NHC