High Quality Content by WIKIPEDIA articles! A typhoon is a mature tropical cyclone that develops in the northwestern part of the Pacific Ocean between 180° and 100°E. This region is referred to as the northwest Pacific basin. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern (North America to 140°W), central (140°W to 180°), and western (180° to 100°E). Identical phenomena in the eastern north Pacific are called hurricanes, with tropical cyclones moving into the western Pacific re-designated as typhoons. The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts is in Japan, with other tropical cyclone warning centers for the northwest Pacific in Honolulu (the Joint Typhoon Warning Center), the Philippines, and Hong Kong. While the RSMC names each system, the main name list itself is coordinated amongst 18 countries, including the United States, who have territories threatened by typhoons each year. The Philippines uses their own naming list for systems which approach the country.