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Annual Tropical Cyclone Report 2013


Executive Summary

The Annual Tropical Cyclone Report (ATCR) is prepared by the staff of the Joint Typhoon Warning Center (JTWC), a jointly manned United States Air Force/Navy organization formally under the operational command of the Commanding Officer, Joint Typhoon Warning Center.

The original JTWC was established on 1 May 1959 by the Commander-in- Chief, US Pacific Command (USCINCPAC) to provide a single tropical cyclone warning center for the western North Pacific region. USCINCPAC delegated the tropical cyclone forecast and warning mission to Commander, Pacific Fleet. A subsequent USCINCPAC directive further tasked Commander, Pacific Air Force to provide for tropical cyclone (TC) reconnaissance support to the JTWC. Currently, JTWC operations are guided by USPACOM Instruction 0539.1 and Pacific Air Forces Instruction 15-101.

This edition of the ATCR documents the TC season and details operationally or meteorologically significant cyclones noted within the JTWC Area of Responsibility. Details are provided to describe either significant challenges and/or shortfalls in the TC warning system and to serve as a focal point for future research and development efforts. Also included are tropical cyclone reconnaissance statistics and a summary of tropical cyclone research or technique development that members of JTWC were involved.

For the first time since 2004, above average tropical cyclone activity was observed in the western North Pacific Ocean, with only 33 TCs observed compared to the long term average of 31. There were five cyclones that reached super typhoon intensity, with Super Typhoon 31W (Haiyan) being one of the strongest cyclones on record for the western North Pacific basin. Major DoD installations experienced minimal impacts, with only one typhoon (23W) and one depression (13W) passing just north of Okinawa. Guam experienced a direct hit by Tropical Storm 25W (Wipha) while it was a tropical depression. Department of Defense bases in South Korea were not impacted and mainland Japan was impacted by two tropical storms, 15W and 16W.

The Southern Hemisphere activity remained below the long term average of 28, with 16 cyclones in the south Indian Ocean / western Australia region and 8 in the south Pacific / eastern Australia region. The Northern Indian Ocean experienced slightly above normal activity with 6 cyclones, with one in the Arabian Sea and five in the Bay of Bengal. The most significant cyclone in the north Indian Ocean was Tropical Cyclone 20B (Phalin), which reached a peak intensity of 140 knots.

Weather satellite data remained the mainstay of the TC reconnaissance mission to support the JTWC. Satellite analysts exploited a wide variety of conventional and microwave satellite data to produce over 9,280 position and intensity estimates (fixes), primarily using the USAF Mark IVB and the USN FMQ-17 satellite direct readout systems. Geo-located microwave satellite imagery overlays available via the Automated Tropical Cyclone Forecast (ATCF) system from Fleet Numerical Meteorology and Oceanography Center and the Naval Research Lab Monterey were also used by JTWC to make TC fixes thus providing additional data for TC location and intensity.

JTWC also continues to utilize radar derived TC position information from numerous U.S. owned/operated weather radars as well as from international sources. However, budget challenges have delayed the replacement of the WSR-88D Doppler Weather Radar at Kadena AB.

JTWC continued to collaborate with TC forecast support and research organizations such as the Fleet Numerical Meteorology and Oceanography Center (FNMOC), Naval Research Laboratory, Monterey (NRLMRY), Naval Post Graduate School, the Office of Naval Research, Air Force Weather Agency (AFWA), and NOAA Line Offices for continued development of TC reconnaissance tools, numerical models and forecast aids. Pg. 4

The Techniques Development (TECHDEV) remained the voice of JTWC to the research and development community. They worked with researchers from the University of Hawaii, University of Arizona, Naval Post Graduate School and other agencies on a variety of promising projects. In collaboration with other Typhoon Duty Officers , TECHDEV developed a cyclone phase checklist to help forecasters assess whether a cyclone is tropical, subtropical or extratropical. This process and checklist was presented at the 2013 AMS Conference on Hurricanes and Tropical Meteorology in San Diego, CA.

Behind all these efforts are the dedicated team of men and women, military and civilian at JTWC. Special thanks to the entire JTWC N6 Department for their outstanding IT support and the administrative and budget staff who worked tirelessly to ensure JTWC had the necessary resources to get the mission done in extremely volatile financial times. A Special thanks also to: FNMOC for their operational data and modeling support; ONR for continuing to provide funding to basic and applied research in tropical cyclones in a very challenging fiscal environment, NRLMRY for its dedicated TC research, including providing real-time access to cutting edge satellite imagery on their Tropical Cyclone Page and improvements to the COAMPS-TC model; the National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service for satellite reconnaissance support; Dr. John Knaff, Mr. Jeff Hawkins, Dr. Mark DeMaria, Mr. Chris Velden and Mr. Derrick Herndon for their continuing efforts to exploit remote sensing technologies in new and innovative ways; Mr. Charles R. “Buck” Sampson, Ms. Ann Schrader, and Mr. Mike Frost for their outstanding support and continued development of the ATCF system.