 Originating in the subtropical west @-@ central Pacific , this large cyclone moved westward to a point south of Japan before becoming a tropical storm . Soon afterward , the system recurved across central Japan on September 2 and evolved into an extratropical cyclone as it returned to the northern Pacific ocean on September 3 . This system was recognized by the Japanese Meteorological Agency as a tropical storm , and the Hong Kong Royal Observatory as a tropical depression . 
