An overview of the present climate in the tropical South Pacific Islands, with an outlook for the coming months, to assist in dissemination of climate information in the Pacific region.
Number 20 – 8 May 2002
April’s Climate: The SPCZ was displaced further south than average about and west of the date line, with a large area of enhanced convection affecting Fiji and Tonga. Another convective band extended from the Southern Cook Islands to the south of French Polynesia. Rainfall was above average at many locations within these convective areas. Rainfall was also above average in northern areas of New Caledonia. An extensive band of divergence extended from the Solomon Islands to the east of the Northern Cook Islands, with below average rainfall in many areas. Rather dry conditions continued on the Queensland coast of Australia, extending into the western Coral Sea, Willis Island having now recorded 9 consecutive months with less than 75% of average rainfall. Exceptionally high mean air temperatures, associated with unusually warm sea surface temperatures, were measured in parts of Fiji and central French Polynesia.
ENSO and sea surface temperatures (SST): It is still possible that an El Niño event will influence the Southwest Pacific climate by September this year. However it may only be weak, as any progress has been slow, with little change occurring in either atmospheric or oceanic conditions in the tropical Pacific over the past month. The Southern Oscillation Index is weakly negative and the equatorial Pacific Ocean remains warmer than average especially off the west coast of South America where enhanced rainfall continued. The next 4-6 weeks remain critical to the establishment of an El Niño episode this year.
Forecast validation: How well are we doing with our predictions?
Three month outlook: Above average rainfall is likely in both Western and Eastern Kiribati, and Tonga, with average or above average totals in Vanuatu and in southern and central French Polynesia. Average to below average rainfall is expected from the Tokelaus to the Marquesas.
Feature Article: No further progress towards an El Niño in the last month.
Sources of South Pacific rainfall data
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