Tropical rainfall outlook: February to April 2006.
A large region of enhanced convection is likely from Fiji southeastwards to the Austral Islands, including Tonga, Niue, the Northern and Southern Cook Islands, and the Society Islands.
Suppressed convection is expected over Western and Eastern Kiribati, where rainfall is forecast to be below average. Rainfall is likely to be near or below average over Tuvalu and the Marquesas Islands.
Rainfall is expected to be near average for the rest of the countries in the region.
The global forecast model skills are moderate for this time of the year, as the wet season continues.
| Island group | Rainfall outlook | Outlook confidence |
|---|---|---|
| Fiji | 15:40:45 (Near or above average) | Moderate |
| Tonga | 15:45:40 (Near or above average) | Moderate |
| Niue | 20:40:40 (Near or above average) | Moderate |
| Northern Cook Islands | 15:45:40 (Near or above average) | Moderate |
| Southern Cook Islands | 20:40:40 (Near or above average) | Moderate |
| Society Islands | 20:40:40 (Near or above average) | Moderate |
| Austral Islands | 20:40:40 (Near or above average) | Moderate |
| Papua New Guinea | 20:50:30 (Near average) | Moderate |
| Solomon Islands | 20:50:30 (Near average) | Moderate |
| Vanuatu | 25:50:25 (Near average) | Moderate |
| Wallis & Futuna | 20:50:30 (Near average) | Moderate |
| Samoa | 20:45:35 (Near average) | Moderate |
| New Caledonia | 30:4030 (Near average) | Moderate |
| Tokelau | 35:45:20 (Near average) | Moderate |
| Tuamotu Islands | 25:50:25 (Near average) | Moderate |
| Pitcairn Island | 20:50:30 (Near average) | Moderate |
| Tuvalu | 40:40:20 (Near or below average) | Moderate |
| Marquesas Islands | 45:40:15 (Near or below average) | Moderate |
| Western Kiribati | 45:30:25 (Below average) | Moderate |
| Eastern Kiribati | 45:35:20 (Below average) | Moderate |
NOTE: Rainfall estimates for Pacific Islands for the next three months are given in the table. The tercile probabilities (e.g., 20:30:50) are derived from the interpretation of several global climate models. They correspond to the odds of the observed rainfall being in the lowest (driest) one third of the rainfall distribution, the middle one third, or the highest (wettest) one third of the distribution. On the long-term average, rainfall is equally likely (33% chance) in any tercile.
Forecast validation: November 2005 to January 2006
Enhanced convection and above average rainfall was expected over the Solomon Islands and the Southern Cook Islands. Near or above average rainfall was expected from Papua New Guinea east-southeast to Pitcairn Island, including Fiji, Wallis & Futuna, Tonga, Samoa, Niue, and the Austral and Tuamotu Islands. Suppressed convection with below average rainfall was forecast for Eastern Kiribati, with near or below average rainfall expected in Tuvalu, Tokelau, and the Marquesas Islands. Near average rainfall was expected elsewhere in the region.
Areas of above average rainfall affected the Solomon Islands, as well as Fiji, Tonga, American Samoa, Niue, and the Marquesas Islands. Suppressed convection or below average rainfall occurred over Western and Eastern Kiribati, extending to the Northern Cook Islands and the Society Islands. Rainfall was higher than expected in the Marquesas Islands, and lower than forecast in New Caledonia, Vanuatu, Western Kiribati, and the Southern Cook Islands. The overall 'hit' rate for the November 2005 – January 2006 rainfall outlook was about 70%. Outcomes for the Solomon Islands (based on OLR anomalies) have been consistent with forecasts for twelve consecutive months.