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 15 – 10 December 2001

November's Climate: The monsoon was well established over Indonesia, northern Australia and Papua New Guinea during November, with outgoing long-wave radiation (OLR) anomalies indicating active convection over these areas, as well as parts of the Solomon Islands. Convection was also enhanced over the seas between New Zealand and Tonga, and over Pitcairn Island. Some areas within these regions received 200% or more of their average rainfall, including islands in the north Tasman Sea and Gambier Island in French Polynesia. Rainfall totals were also enhanced over Samoa and northern New Zealand. Below average rainfall continued during November in the Coral Sea and throughout central Tonga. Rainfall was also below average in many areas from New Caledonia across to French Polynesia, including Kiribati. ‘Trina’, the first tropical cyclone of the season developed near the Southern Cook Islands on 30 November.

ENSO and sea surface temperatures (SST): The three-month mean Southern Oscillation Index (SOI) was close to zero. The November value was +0.6, indicating a slight La Niña component. However, overall atmospheric conditions and sea surface temperature (SST) anomalies remain weak and are expected to continue in the neutral range throughout the Southwest Pacific for the next three to six months.

Forecast validation: How well are we doing with our predictions?

Three month outlook: The trade winds are still expected to remain slightly enhanced across the central Pacific promoting below average to average rainfall in Tokelau, Eastern Kiribati, Samoa, the Northern Cook Islands, and the Marquesas Islands. Average to above average rainfalls are indicated for many places west of 170°E and south of 20°S.

Feature Article: Forecasting climate – the odds on getting it right.

Sources of South Pacific rainfall data

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