Three-month outlook
Tropical rainfall outlook: March to May 2006.
Rainfall outlook map for March to May 2006. (Click for enlargement)
Suppressed convection is expected in the equatorial region of Western and Eastern Kiribati, where rainfall is expected to be below average.
Near or below average rainfall is likely in Tuvalu, east to the Marquesas and Tuamotu Islands including Tokelau and the Northern Cook Islands.
Regions of near or above average rainfall expected from Fiji east-southeast to Pitcairn Island including, Tonga, the Southern Cook Islands, and the Austral Islands. Rainfall is also expected to be near or above average in Papua New Guinea.
Near average rainfall is forecast for the rest of the countries in the region.
The global rainfall model skill is around moderate for this time of the year as the end of the tropical cyclone season approaches.
On average, there are two to three tropical cyclone occurrences in March.
| Island group | Rainfall outlook | Outlook confidence |
|---|---|---|
| Papua New Guinea | 15:40:45 (Near or above average) | Moderate – high |
| Fiji | 20:40:40 (Near or above average) | Moderate |
| Tonga | 20:40:40 (Near or above average) | Moderate |
| Southern Cook Islands | 20:40:40 (Near or above average) | Moderate |
| Austral Islands | 20:40:40 (Near or above average) | Moderate |
| Pitcairn Island | 20:40:40 (Near or above average) | Moderate |
| Solomon Islands | 25:40:35 (Near average) | Moderate |
| New Caledonia | 25:40:35 (Near average) | Moderate |
| Vanuatu | 25:40:35 (Near average) | Moderate |
| Samoa | 25:45:30 (Near average) | Moderate |
| Niue | 25:40:35 (Near average) | Moderate |
| Wallis & Futuna | 30:40:30 (Near average) | Moderate |
| Society Islands | 20:45:35 (Near average) | Moderate |
| Tuvalu | 40:40:20 (Near or below average) | Moderate |
| Tokelau | 40:45:15 (Near or below average) | Moderate |
| Northern Cook Islands | 40:40:20 (Near or below average) | Moderate |
| Tuamotu Islands | 40:40:20 (Near or below average) | Moderate |
| Marquesas Islands | 40:40:20 (Near or below average) | Moderate |
| Western Kiribati | 45:30:25 (Below average) | Moderate – high |
| Eastern Kiribati | 45:30:25 (Below average) | Moderate – high |
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: December 2005 to February 2006
Suppressed convection with below average rainfall was expected over Western and Eastern Kiribati, extending to the Northern Cook Islands and the Marquesas Islands. Rainfall was expected to be near or below average over Tuvalu, Tokelau, and the Tuamotu Islands. A large region of near or above average rainfall was forecast from the Solomon Islands southeast to the Austral Islands, including Vanuatu, Fiji, Wallis and Futuna, Tonga, Samoa, Niue, the Southern Cook Islands, and the Society Islands, with near average rainfall elsewhere.
Areas of enhanced convection and above average rainfall affected Papua New Guinea and the northern Solomon Islands, extending southeast to include parts of Fiji, Wallis and Futuna, Tonga, Samoa, and Niue. Suppressed convection or below average rainfall occurred over Western and Eastern Kiribati, extending to the Northern Cook Islands. Rainfall was higher than expected in Samoa and Northern French Polynesia, and lower than forecast in Vanuatu. The overall rainfall outcome was similar to what was expected, with a 'hit' rate for the December 2005-February 2006 outlook of about 80%.