Joint Typhoon Warning Center The Joint Typhoon Warning Center ( JTWC ) is a joint United States Navy – United States Air Force task force located in Pearl Harbor , Hawaii . The JTWC is responsible for the issuing of tropical cyclone warnings in the North West Pacific Ocean , South Pacific Ocean and Indian Ocean for United States Department of Defense interests , as well as U . S . and Micronesian civilian interests within the command ' s area of responsibility ( AOR ) . The JTWC provides support to all branches of the U . S . Department of Defense and other U . S . government agencies . Their products are intended for the protection of primarily military ships and aircraft as well as military installations jointly operated with other countries around the world . History . The beginning of the formation of a typhoon warning center in the Pacific occurred in the wake of Typhoon Cobra on December 18 , 1944 . A small but significant typhoon east of the Philippines , Typhoon Cobra led to the largest naval disaster in United States history with 790 lives lost , and was the worst United States military loss from a tropical cyclone impact since 1889 . Due to this typhoon , weather stations were established in Caroline Islands , and eventually in Manila , Iwo Jima , and Okinawa . New weather central offices ( for coordinating data ) were established at Guam and Leyte . JTWC was originally established in 1959 at Nimitz Hill , Guam combined the efforts of the former naval centers located in Guam , Hawaii , and the Philippines with the Air Force center in Japan . In November 1962 , Typhoon Karen destroyed the building housing the Fleet Weather Center / Joint Typhoon Warning Center . It relocated in a more typhoon - proof building in 1965 . It was relocated to Pearl Harbor on January 1 , 1999 due to the 1995 Base Realignment and Closure ( BRAC ) round . Standards and practices . A more modernized method for forecasting tropical cyclones had become apparent by the 1980s . Prior to the development of ATCF , the tools used by the Department of Defense to forecast tropical cyclone track were acetate . grease pencils , and disparate computer programs . The ATCF software was developed by the Naval Research Laboratory for the JTWC beginning in 1986 , and used since 1988 . It was adapted for use at the National Hurricane Center ( NHC ) in 1990 . JTWC adheres to the World Meteorological Organization ' s ( WMO ) rules for storm names and adheres to acknowledged guidelines for intensity of tropical cyclones and tropical storms , with the exception of using the U . S . standard of measuring sustained winds for 1 - min instead of the 10 - min span recommended by the WMO ( see Saffir - Simpson Hurricane Scale ) . The JTWC is not one of the WMO designated Regional Specialized Meteorological Centre s , nor one of its Tropical cyclone warning centres , as its main mission is to support the United States Navy and remainder of the federal government . JTWC monitors , analyzes , and forecasts tropical cyclone formation , development , and movement year round . Its area of responsibility covers 89 % of the world ' s tropical cyclone activity . Staffing . The Center is manned by 20 U . S . Air Force and Navy personnel . The JTWC uses several satellite systems and sensors , radar , surface and upper level synoptic data as well as atmospheric models to complete its mission .