Forecast validation

Forecast validation

Forecast period: August to October

Average to above average rainfall was expected over many islands from Papua New Guinea across to the Southern Cook Islands. Below average rainfalls were forecast for Samoa and the Tokelaus, with average to below average rainfall in Kiribati, Tuvalu, the Northern Cooks and Pitcairn Island. Near average rainfalls were expected in most other parts of the tropical South West Pacific.

This scenario was correct for many islands north of 15°S and west of 180°, including Eastern Kiribati. Rainfall was lower than expected for most other regions, especially Tonga and Niue, where below average rainfall resulted when above average was expected. The overall ‘hit rate’ for the August to October rainfall outlook was only 55%, possibly because many global forecast models still contained a significant La Niña bias, when the ENSO state was neutral.