Tropical rainfall outlook: October to December 2007
A La Niña-like pattern, with the SPCZ displaced further southwest than usual. A large region of enhanced convection is expected from the Solomon Islandssoutheast to Niue, with above average rainfall likely over the Solomon Islands, Vanuatu, New Caledonia, Fiji, Tonga, Niue, and Samoa.
Average or above average rainfall is expected in Papua New Guinea, the southern Cook Islands, Society and Austral Islands.
Suppressed convection is expected in the equatorialPacific over Western and Eastern Kiribati, with below average rainfall.
Near or below average rainfall is likely in Tokelau, the Northern Cook Islands, and Tuvalu.
Near average rainfall is expected in Wallis and Futuna, Tuamotu Islands, Marquesas Islands, and Pitcairn Island.
Confidence in the forecast model skill, for this seasonal outlook, is moderate for most Pacific Island countries. In the past, the average region-wide hit rate for forecasts issued in October has been 58%, a little lower than the long term average for all months combined.
| Island group | Rainfall outlook | Outlook confidence |
|---|---|---|
| Solomon Islands | 20:35:45 (Above) | Moderate |
| Vanuatu | 20:30:50 (Above) | High |
| New Caledonia | 20:35:40 ((Above) | Moderate-High |
| Fiji | 20:35:45 (Above) | Moderate |
| Tonga | 20:30:50 (Above) | High |
| Niue | 25:30:45 (Above) | Moderate |
| Samoa | 20:35:45 (Above) | Moderate |
| Papua New Guinea | 20:40:40 (Near or above) | Moderate |
| Southern Cook Islands | 20:40:40 (Near or above) | Moderate |
| Society Islands | 20:40:40 (Near or above) | Moderate |
| Austral Islands | 40:40:40 (Near or above) | Moderate |
| Wallis & Futuna | 25:40:35 (Near average) | Low |
| Tuamotu Islands | 30:40:30 (Near average) | Low |
| Marquesas | 35:45:20 (Near average) | Moderate |
| Pitcairn Island | 25:40:35 (Near average) | Low |
| Tokelau | 40:40:20 (Near or below) | Moderate |
| Northern Cook Islands | 40:40:20 (Near or below) | Moderate |
| Tuvalu | 40:40:20 (Near or below) | Moderate |
| Western Kiribati | 50:30:20 (Below) | High |
| Eastern Kiribati | 50:30:20 (Below) | 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.