July
Monthly climate
ENSO & SST
Forecast validation
Three-month outlook
Feature article
Tropical Pacific rainfall
Data sources
Adaptation behaviour before to the 2004/05 tropical cyclone season in the Cook Islands
Imogen Ingram, Te Pa Mataiapo, Rarotonga, Cook Islands
February 2005 will remain memorable in the Cook Island’s history as five tropical cyclones battered the small island nation in that month, one after the other. A summary of the five cyclones – Meena, Nancy, Olaf, Percy, and Rae can be found in Issue 56 of the Island Climate Update (May 2005).
Meena affected the northern part of the country, and Nancy caused havoc over the eastern coast of the main island of Rarotonga.
Forecast validation
Forecast period: April to June 2005
Average or above average rainfall was expected in Western Kiribati and the Northern Cook Islands. Suppressed convection with below average rainfall was expected in the Marquesas Islands with near or below average rainfall in Eastern Kiribati, Fiji, Samoa, and the Austral Islands. Rainfall was expected to be near average rainfall elsewhere in the region.
Areas of below average rainfall occurred from Tokelau to the Austral Islands, including the Cook Islands and the Society Islands, as well as northern New Zealand.
ENSO and Sea Surface Temperatures
The tropical Pacific Ocean is in a neutral state (no El Niño or La Niña), but equatorial Pacific sea surface temperature (SST) anomalies remain positive. The Southern Oscillation Index (SOI) rose to near zero in June, after a strong negative excursion in May. The 3-month April – June mean SOI was –0.9. The NINO3, NINO4, and NINO3.4 SST anomalies were all between +0.6 and +0.7 °C for June, and for April – June.
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 58 – July 2005
June's climate: South Pacific Convergence Zone rather weak. Above average rainfall in parts of Fiji, the Wallis and Futuna Islands, Tonga, and American Samoa. Below average rainfall in parts of Western Kiribati, New Caledonia, and northern and central French Polynesia, Niue, Tuvalu, and Vanuatu.
Climate developments in June 2005
The South Pacific Convergence Zone (SPCZ) was rather weak in June, affecting the region northeast of the Solomon Islands. North of the equator, the Inter-tropical Convergence Zone (ITCZ) extended from the Caroline Islands across the Date Line to the equatorial region well south of Hawaii. Areas of enhanced convection occurred from Tonga to the Austral Islands of Southern French Polynesia, and also over Australia and the North Tasman Sea.
Tropical rainfall outlook: July to September 2005
The tropical Pacific is in neutral ENSO conditions and this is likely to influence the rainfall patterns across the region.
Enhanced convection is expected in the equatorial region from the Solomon Islands to the Marquesas Islands, including Western Kiribati, Tuvalu, Tokelau, and the Northern Cook Islands, where rainfall is expected to be near or above average.
Rainfall is forecast to be near or below average for Fiji, Tuamotu Islands of French Polynesia, and Pitcairn Island.
Tropical pacific rainfall - June 2005
Territory and station name
June 2005 rainfall total (mm)
Long-term average (mm)
June 2005 percent of average
Lowest on record (mm)
Highest on record (mm)
Records began
American Samoa
Pago Pago Airport
340.2
161
211
1966
Australia
Cairns Airport
32.8
48
68
3
144
1941
Townsville Airport
34.4
20
172
0
107
1940
Brisbane Airport
152.0
71
214
1
701
1929
Sydney Airport
63.0
126
50
1929
Cook Islands
Penryhn
117.8
143
82
13
570
1937
Rarotonga Airport
131.6
112
118
9
280
1929
Rarotonga EWS
127.8
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