Island Climate Update 15 - December 2001

Tropical Cyclones
‘Trina’, the first tropical cyclone of the season
‘Trina’ developed at 21°S 160°W near Rarotonga in the Southern Cook Islands on 30 November, with estimated maximum sustained winds of 65 km/h. Winds at Rarotonga Airport gusted between 100 and 104 km/h at times between 30 Nov 0110 UTC and 1 December 2100 UTC. Some flooding was reported. The system moved northeast decaying to tropical storm intensity by 2 December 2100 UTC.

Forecast validation
Forecast period: September to November
Average to above average rainfall was expected in a band from Vanuatu, across Fiji, southeast to the Southern Cooks, the SPCZ being more active than usual in this region. Below average rainfalls were forecast for a broad area from Tuvalu to the Marquesas, including the Austral, Society and Tuamotu Islands of French Polynesia.

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.

ENSO and Sea Surface TEmperatures
Warmer than average seas around Nauru
SST anomalies have still shown little change since the middle of the year, with an area of warm 30°C surface waters and positive SST anomalies (at least 1.0°C above average) around Nauru, between the Solomon Islands and Western Kiribati. SST anomalies also continued above average about and to the east of the Tuamotu Islands and were well above average south of the Cook Islands.

Climate developments in November 2001
Monsoon well established in the northwest
Areas of below average rainfall from the Coral Sea across to French Polynesia
The monsoon was well established over Indonesia, northern Australia and Papua New Guinea during November, with outgoing long-wave radiation (OLR) anomalies below average, 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.

Rainfall outlook for December 2001 to February 2002
Average to above average rainfall in the western Pacific, Coral Sea, trending towards average or below average further east and northeast
In November the SPCZ was displaced further north than usual east of Samoa, but near its average position elsewhere. However, December through February trade winds are expected to remain slightly enhanced across the central Pacific pushing the SPCZ a little further south than usual.