NEW : Omar becomes Category 3 hurricane as it approaches Leeward Islands . U.S. Coast Guard shuts down Christiansted Island , where refinery is . A tropical storm watch is in effect for Guadeloupe . Parts of Puerto Rico will see 20 inches of rain , wind , flash floods . Omar is 15th named storm of hurricane season , which ends November 30 .
NEW : Omar becomes Category 3 hurricane as it approaches Leeward Islands . U.S. Coast Guard shuts down Christiansted Island , where refinery is . Parts of Puerto Rico will see 20 inches of rain , wind , flash floods . Omar is 15th named storm of hurricane season , which ends November 30 .