Rainfall outlook for March to May 2002
Below average rainfall in equatorial latitudes from Tokelau east, mainly average rainfall in other areas; trending towards above average in Western Kiribati, and Fiji across to Niue.
The trades were again slightly stronger in February east of the dateline, and weaker to the west. The SPCZ was located from east of the Solomon Islands, across Fiji and Tonga: displaced south of its normal position. Rainfall is projected to be above average in Niue, and average to above average from Fiji across to Tonga, and in Western Kiribati. Below average rainfall is likely in a large part of the east of the region north of about 12°S from Tokelau to the Marquesas, including Eastern Kiribati. Average rainfall is expected in the other parts of the region.
Rainfall outlook for January to March 2002
Probabilities of rainfall departures from average
Broad-scale rainfall patterns and anomalies in the southern tropical Pacific area estimated from the state of large-scale regional climate factors, such as La Niña or El Niño, their effect on the South Pacific and Tropical Convergence Zones, surface and sub-surface sea temperatures, and computer models of the global climate. Rainfall estimates for the next three months for Pacific Islands are given in the adjacent table. The terciles (e.g. 20:30:50) are derived from the interpretation of several global climate models. They correspond to the lowest (driest) one third of the rainfall distribution, the middle one third, and the highest (wettest) one third of the distribution. On the long-term average, rainfall is equally likely (33% chance) in any tercile. The probabilities shown express the expected shift in the distribution from the long-term average, based on predictions of oceanic and atmospheric conditions. The amount of inter-model forecast consistency is indicated by the levels of confidence expressed in the table.
| Island Group | Rainfall Outlook | Low: Mid: Top | Confidence |
|---|---|---|---|
|
Niue |
Above |
20:30:50 |
Moderate |
|
Western Kiribati |
Average to above |
20:45:35 |
Low |
|
Fiji |
Average to above |
20:40:40 |
Low |
|
Tonga |
Average to above |
20:40:40 |
Low |
|
Papua-New Guinea |
Average |
15:60:25 |
Moderate |
|
Solomon Islands |
Average |
20:50:30 |
Moderate |
|
Vanuatu |
Average |
30:55:15 |
Moderate |
|
New Caledonia |
Average |
30:30:40 |
Low |
|
Wallis & Futuna |
Average |
30:45:25 |
Low |
|
Southern Cook Islands |
Average |
20:55:25 |
Moderate |
|
Society & Tuamotu Islands |
Average |
30:50:20 |
Low |
|
Austral Islands |
Average |
10:55:35 |
Moderate |
|
Samoa |
Average |
25:50:25 |
Low |
|
Pitcairn Island |
Average |
30:50:20 |
Moderate |
|
Tuvalu |
Average to below |
40:40:20 |
Low |
|
Tokelau |
Below |
50:35:15 |
Moderate |
|
Northern Cook Islands |
Below |
55:30:15 |
Moderate |
|
Eastern Kiribati |
Below |
50:35:15 |
Moderate |
|
Marquesas |
Below |
60:30:10 |
Moderate |
Rainfall outcomes as estimated from models and historical records. The second column indicates the probability of top (above), middle (average) or bottom (below) tercile rainfall, where a percentage is given. The rainfall outlook is subjectively estimated probability of bottom:middle:top tercile.