NEW : Omar becomes Category 3 hurricane as it approaches Leeward Islands . MIAMI , Florida ( CNN ) -- U.S. Coast Guard shuts down Christiansted Harbor , where refinery is . Parts of Puerto Rico could see 20 inches of rain , mudslides , flash floods . Comment: The storm has been moving west and will continue to move east until it reaches the Bahamas on Friday or Saturday night.
NEW : Omar becomes Category 3 hurricane as it approaches Leeward Islands . U.S. Coast Guard shuts down Christiansted Harbor , where refinery is . Parts of Puerto Rico could see 20 inches of rain , mudslides , flash floods . Comment: The storm has been moving west and will continue to move east until it reaches the Bahamas on Friday or Saturday night.