Rainfall outlook for February to April 2002
SPCZ More active in the west Below average rainfall in equatorial latitudes from Kiribati east, mainly average rainfall in other areas; trending towards above average in the Solomons and Fiji.
The SPCZ is likely to be displaced slightly south of its normal location in the west, from February through April, with enhanced trades east of the dateline and weaker trades to the west. Rainfall is projected to be below average in a large part of the equatorial Pacific from Western Kiribati across to the Marquesas Islands, and including Tuvalu, the northern Cook Islands, Tokelau and Eastern Kiribati. Average rainfall is expected in many other areas south of 15°S including Papua-New Guinea, Vanuatu, New Caledonia, Tonga and Niue, and from the Southern Cook Islands across to many parts of French Polynesia and Pitcairn Island. Areas of above average rainfall are likely in parts of the Solomon and Fiji island groups.
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 | Confidence | |
|---|---|---|---|
| Solomon Islands | Average to above average | 20:40:40 | Moderate |
| Fiji | Average to above average | 10:50:40 | Moderate |
| Papua New Guinea | Near average | 15:60:25 | Moderate |
| Vanuatu | Near average | 15:55:30 | Moderate |
| New Caledonia | Near average | 25:45:30 | Moderate |
| Tonga | Near average | 20:60:20 | Moderate |
| Niue | Near average | 15:55:30 | Moderate |
| Southern Cook Islands | Near average | 25:60:15 | Moderate |
| Austral Islands | Near average | 25:60:15 | Moderate |
| Pitcairn Island | Near average | 15:60:25 | Moderate |
| Samoa | Near average | 30:55:15 | Moderate |
| Society and Tuamotu Islands | Near average | 20:45:35 | Moderate |
| Wallis & Futuna | Average to below average | 40:40:20 | Low |
| Western Kiribati | Below average | 55:35:10 | Moderate |
| Tuvalu | Below average | 55:35:10 | Moderate |
| Tokelau | Below average | 55:35:10 | Moderate |
| Northern Cook Islands | Below average | 60:30:10 | Moderate |
| Eastern Kiribati | Below average | 60:30:10 | Moderate |
| Marquesas | Below average | 60:25:15 | High |
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.