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 38 – 8 November 2003
October’s climate: Rainfall was below average over much of the Southwest Pacific from the Caroline Islands to Eastern Kiribati, and from the region east of Vanuatu to Samoa, including Fiji. The South Pacific Convergence Zone (SPCZ) extended from the north of Papua New Guinea, east to Tuvalu, and from the Tuamotu Islands of French Polynesia to the region around Pitcairn Island (where rainfall was above average). October’s rainfall was also above average over parts of Vanuatu and New Caledonia, the Kermadec’s, northern New Zealand, and the Southern Cook Islands. Air temperatures were above average in tropical Southwest Pacific Islands within a few degrees of the equator, as well as the Marquesas Islands of French Polynesia. It was extremely warm in Samoa.
ENSO and sea surface temperatures (SST): Even though the equatorial Pacific sea surface temperatures (SST) are warmer than average, most of the El Niño Southern Oscillation (ENSO) indicators are showing a neutral state, which is likely to continue through to the end of the southern hemisphere summer. The chances of an El Niño occuring during this time of year is minimal. The Southern Oscillation Index (SOI) remained unchanged at -0.3 for October. The global climate models suggest that the equatorial Pacific will remain in a neutral state through the rest of this year and into early 2004.
Forecast validation: How well are we doing with our predictions?
Three month outlook: The three-month forecast period coincides with the start of the wet and tropical cyclone season in the southern hemisphere. Based on the global climate forecast models, enhanced convection is expected over Papua New Guinea, the Solomon Islands, Samoa, the Society Islands and Tuamotu Islands. Suppressed convection is likely in the equatorial region from Eastern Kiribati eastwards to the Marquesas Islands. Normal or below normal rainfall is expected from Vanuatu east to Niue, including Fiji and Tonga. Near normal rainfall is likely everywhere else in the region.
Feature article: Slightly higher risk of tropical cyclones for South Pacific countries near the date line.
Sources of South Pacific rainfall data.
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