Island Climate Update 20 - May 2002

Tropical cyclones
April was a ‘quiet’ month
There were no further tropical cyclones in the Southwest Pacific during April. Five tropical cyclones have occurred so far this season, which is the same number as last season and well below average. There is a 50 percent chance of another tropical cyclone occurring in May.
ENSO update
No further progress towards an El Niño in the last month
There is still about a 60% chance of an El Niño event affecting the Southwest Pacific climate by September this year.

Forecast validation
Forecast period: February to April 2002
The SPCZ was expected to be more active and further south of its usual position west of the date line, with enhanced trade winds in the east. Areas of above average rainfall were forecast for parts of the Solomon Islands and Fiji. Below average rainfall was forecast for many islands from Western Kiribati across to the Marquesas Islands.

ENSO and Sea Surface Temperatures
In the tropical Southwest Pacific, a band of much warmer than usual water at the surface (at least 1.0°C above average) extends from the Solomon Islands southeast to affect Vanuatu, Fiji, Tonga, Niue, and the region south of the Southern Cook Islands. Surface waters at least 1.0°C above average also encompass the region from central French Polynesia to the east of Pitcairn Island, as well as Western Kiribati.

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.

Climate developments in April 2002
Active convection over Fiji and Tonga
High rainfall in parts of New Caledonia
Low rainfall from the Solomon Islands across to the northern Cook Islands
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, with another convective band further east extending from the Southern Cook Islands to the south of French Polynesia.

Rainfall outlook for May to July 2002
Above average rainfall in equatorial latitudes from west to east, including Tonga
Average to below average rainfall from Tokelau to the Marquesas Islands
Mainly average rainfall in other areas
The South Pacific Convergence Zone was further south than average about and west of the date line during April, lying across southern Fiji, and extending east to the Southern Cook and Austral Islands. Rainfall is projected to be above average in Western and Eastern Kiribati, as well as Tonga.

Sources of South Pacific rainfall data
This bulletin is a multi-national project with important collaboration from the following Pacific nations:
American Samoa
Australia
Cook Islands
Fiji
French Polynesia
Kiribati
New Caledonia
New Zealand
Niue
Papua New Guinea
Pitcairn Island
Samoa
Solomon Islands
Tokelau
Tonga
Tuvalu
Vanuatu
Requests for Pacific island climate data should be directed to the Meteorological Services concerned.
Acknowledgements
This bulletin is made possible with financial support from the New Zealand Agency for International Development (NZAID), Wellington, New Zealand, wi