Pacific ENSO Update

3rd Quarter, 2005 Vol. 11 No. 3

TROPICAL CYCLONE ACTIVITY (2nd Quarter Summary)

PEAC 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 Japanese Meteorology Agency (JMA), which is the World Meteorological Organization's Regional Specialized Meteorological Center (RSMC) for the basin. PEAC 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 when appropriate.

During January through June 2005, the JTWC numbered only four tropical cyclones in the western North Pacific: TC 01W (January), TC 02W (March), TC 03W (April), and TC 04W (May). The JMA named them Kulap, Roke, Sonca, and Nesat respectively. Normally there are approximately six numbered tropical cyclones in the western North Pacific basin during the first six months of the year, and seventeen through August. By the end of August, the western North Pacific had experienced fourtenn numbered tropical cyclones, continuing the below normal activity noted in the first half of 2005. While in their formative stages, about half of the tropical cyclones of the western North Pacific occurring through August 2005 brought some rainfall to the islands in the northwestern portions of Micronesia: Guam, Yap, and Palau. After a burst of tropical cyclone activity in the South Pacific during the February and March of 2005, activity ended in April when cyclone Ingrid moved westward across northern Australia and tropical storm Sheila (not numbered by the JTWC, but named by the Fiji RSMC) passed near Niue as a weak tropical storm.