Located at Naval Base Pearl Harbor, Hawaii, the Joint Typhoon Warning Center (JTWC) is the U.S. Department of Defense agency responsible for issuing tropical cyclone warnings for the Pacific and Indian Oceans.
Official JTWC support is provided to all branches of the U.S. Department of Defense, and other U.S. government departments and their agencies such as the State Department (U.S. Embassies and Consulates), and the Department of Commerce (U.S. National Weather Service).
JTWC products are intended for use by operational units in making decisions on ship movements, aircraft sorties and operational planning and by other government agencies in their respective support and international cooperation roles. For example, the U.S. National Weather Service, in close cooperation with JTWC, utilizes JTWC tropical cyclone warnings to provide local scale forecasts for the various political entities that exist in the geographical region known as Micronesia.
Although not an official member or participant in the United Nations World Meteorological Organization (WMO), JTWC continually attempts to maintain cordial relations with WMO tropical cyclone forecast centers to minimize the issuance of conflicting information.
JTWC tropical cyclone warning support is conducted 24 hours a day, 365 days a year. JTWC monitors, analyzes, and forecasts tropical cyclone genesis, development, and movement across more than 110 million square miles of the Pacific and Indian Oceans from the west coast of the Americas to the east coast of Africa. This area of responsibility encompasses more than 90% of the world's tropical cyclone activity.
Manned by 26 U.S. Air Force and Navy personnel, JTWC uses a vast array of data sources and computational resources in fulfillment of the stated mission. These sources include numerous meteorological satellite systems and sensors, radar data, surface and upper level synoptic data and numerical atmospheric models.
JTWC was established in 1959 and was located at Nimitz Hill, Guam for the first 40 years. Due to the Base Realignment and Closure (BRAC) legislation of 1995, JTWC moved from Guam to Pearl Harbor, Hawaii on 1 Jan 1999.