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 35 – 6 August 2003
July’s climate: The South Pacific Convergence Zone (SPCZ) was active west of the Date Line. However, there was little activity in the east. Rainfall was well above average over much of New Caledonia and Vanuatu. Some locations in New Caledonia recorded 500 mm for the month, after torrential rainfall totalling about 400 mm fell over a two-day period. Rainfall was also above average in parts of Tonga and areas of the Tuamotu Islands of French Polynesia. Well below average rainfall occurred along the equator from Eastern Kiribati eastwards to French Polynesia. Rainfall was also below average in parts of Fiji. Air temperatures were near average throughout much of the tropical Southwest Pacific. However, they were above average in Tuvalu and the Southern Cook Islands.
ENSO and sea surface temperatures (SST): The cooling of sea surface temperatures (SSTs) seen in May, has dissipated rapidly over last few months. The equatorial ocean and atmosphere are in a neutral state. The Southern Oscillation Index (SOI) rose to +0.3 during July. Neutral conditions are expected to prevail in the tropical Pacific until the end of 2003.
Forecast validation: How well are we doing with our predictions?
Three month outlook: The SPCZ is expected to be near its normal position for the forecast period. Above average rainfall is expected in Tuvalu and Tokelau while Papua New Guinea, the Solomon Islands, Wallis and Futuna and Samoa are expected to experience average or above average rainfall. Average or below average rainfall is likely from Western Kiribati trending east-southeast to the Marquesas Islands. Another region of average or below average rainfall is expected from Vanuatu to the Society Islands including Fiji, Tonga, Niue, the Southern Cook Islands and the Marquesas Islands. Below average rainfall is expected in Eastern Kiribati.
Feature article: ENSO Update.
Sources of South Pacific rainfall data.
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