TROPICAL CYCLONE ACTIVITY

2007 Summary

The 2007 North Pacific tropical cyclone season was below normal in almost every category of activity (e.g., numbers of typhoons). The JTWC numbered 26 tropical cyclones in the western North Pacific basin during 2007 (5 below average). Of these 26 cyclones: 3 were tropical depressions, 8 were tropical storms, 15 were typhoons and 4 of the typhoons were super typhoons. This corresponds to normal values of 3, 10, 18, and 4 for these statistics, respectively. The JMA named 22 of the cyclones that JTWC numbered, as well as two cyclones (Haiyan and Podul) which the JTWC did not number. In addition, the JTWC numbered one tropical storm and three tropical depressions that the JMA did not name or number. Tropical cyclone activity in the western North Pacific basin was also shifted westward and northward, which is typical during La Niña. Because of this major shift of basin cyclone activity, no area of Micronesia was severely impacted by a tropical cyclone during 2007. However, several of the basin’s cyclones passed through Micronesia during the early stages of development, each providing a welcome episode of heavy showers.

The tropical cyclone activity in the eastern North Pacific (historically the world’s 2nd most active basin) was well below normal. During 2007, the National Hurricane Center, Miami, named 11 cyclones there (5 below average). Of the 11 named cyclones, only 4 became hurricanes, and of the hurricanes only one of them (Hurricane Flossie) became a major hurricane (i.e., a hurricane with a Category 3, 4 or 5 intensity on the Saffir-Simpson hurricane damage potential scale). Normally there are 8 or 9 hurricanes in the eastern North Pacific, of which 4 typically reach major hurricane status. Only two of the eastern North Pacific hurricanes affected Hawaii: Hurricane Cosme and Hurricane Flossie. Cosme was dissipating as it passed well to the south of Hawaii. Flossie was a major hurricane on its approach to the Big Island of Hawaii, and it yielded a glancing blow of wind, rain and high surf to the Big Island as it passed to the south while on a weakening trend. No tropical cyclones were numbered or named by the central Pacific Hurricane Center, Honolulu.

The 2007-2008 hurricane season in the South Pacific is off to a near-normal start. There have been 4 cyclones named by the responsible agencies in this basin from July 2007 through mid-January 2008. Typical of La Niña years, the focus of tropical cyclone activity in the South Pacific has been between northeastern Australia and Fiji. In ENSO neutral years, the tropical cyclone activity of the South Pacific is more likely to extend eastward to the region of Samoa; during El Niño years, activity can extend as far east as the Cook Islands and French Polynesia. The activity occurs further eastward in a rough proportion to the strength of El Niño and further westward in a rough proportion to the strength of La Niña.

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The PEAC Center archives western North Pacific tropical cyclone numbers, track coordinates, and 1 minute average maximum sustained wind taken from operational warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii. Western North Pacific tropical cyclone names are obtained from warnings issued by the Japan Meteorology Agency (JMA), which is the World Meteorological Organization's Regional Specialized Meteorological Center (RSMC) for the western North Pacific basin. The PEAC Center archives South Pacific tropical cyclone names, track coordinates, central pressure, and 10 minute average maximum sustained wind estimates from advisories issued by the Tropical Cyclone Warning Centers at Brisbane, Nadi, and Wellington. The numbering scheme and the 1-minute average maximum sustained wind estimates are taken from warnings issued by the JTWC. There are sometimes differences in the statistics (e.g., storm maximum intensity) for a given tropical cyclone among the agencies that are noted in this summary.