 The initial tropical disturbance formed just west of the International Dateline within the monsoon trough on October 3 . The system moved westward for nearly a week without significant development . Becoming a tropical depression on October 9 and a tropical storm on October 11 , the cyclone turned to the west @-@ northwest , moving through the central Philippines into the South China sea . Turning more northerly , Ellen intensified to a typhoon while paralleling the west coast of Luzon on October 14 . By October 15 , Ellen 's track became increasingly more westerly due to a building surface high pressure area to its north . Weakening began due to westerly winds aloft and land interaction with China , and Ellen dropped back to tropical storm strength on October 17 . The cyclone moved south of Hong Kong and north of Hainan Island into mainland China on October 19 . In Hong Kong , winds gusted to 78 knots ( 144 km / h ) at Tai Mo Shan . As it neared the border between Vietnam and China , Ellen dissipated on October 20 . 
