Neutral conditions in the tropical Pacific (neither El Niño nor La Niña) were forecast to persist through January-February-March 2013. This outlook was correctly forecast with the Southern Oscillation Index (SOI), trade winds, and tropical cloud patterns all continuing at neutral levels.
Lower than normal pressures were expected in the south Tasman and to the southeast of the Chatham Islands, with enhanced south-westerly winds over New Zealand during the January-February-March period. Much higher pressures than expected however occurred over the New Zealand region extending well east of the country.
Predicted rainfall: rainfall is likely to be near normal or above normal in west and south of the South Island, but near normal or below normal in the east of the North Island. Near normal rainfall is likely for remaining regions.
Outcome: It was much drier than expected across most areas of the North Island and coastal fringes of the West Coast of the South Island; however, as expected near normal and above normal rainfall were recorded in alpine areas of the South Island. Much wetter conditions than normal were recorded in the north-east of the South Island.
Predicted air temperature: temperatures are likely to be near average or below average in the west of the North Island, and near average in all other regions.
Outcome: Near average temperatures were correctly forecast for all regions, although it was slightly warmer than expected in the central North Island and southern districts of the South island.