Retrospective - August to October Outlook

Conditions in the tropical Pacific were on the brink of El Niño at the start of this forecast period, and El Niño development was signalled during August-October. Tropical Pacific Ocean temperatures did reach the El Niño threshold, but the atmosphere has yet to show any significant response to the warmer than normal sea surface temperatures. In the New Zealand region, the stronger than normal spring westerlies often associated with El Nino periods were not expected to be very prominent, with higher pressures than usual expected instead south of the country. In actual fact, lower pressures prevailed across New Zealand and to the south during the season, producing a northwest anomaly over the country.

Predicted rainfall: Rainfall totals are likely to be near normal or above normal in the north of the North Island, below normal for the eastern South Island, and near normal in all other regions.

Outcome: For the North Island near normal rainfall was observed across northern areas and normal to below normal rainfall was observed elsewhere. It was a very wet season across most of the South Island apart from Tasman, Marlborough, parts of North Canterbury and much of Otago where normal to below normal rainfall was recorded.

Predicted air temperature: Temperatures are likely to be near average or above average for all regions of the country. Nevertheless, cold snaps, frosts and snowfalls typical of early spring may still occur from time to time

Outcome: Temperatures were correctly forecast for coastal Nelson, Marlborough, Canterbury, Otago, coastal Southland, Northland, Auckland, much of the southwest North Island, and the Wairarapa. Temperatures were cooler than forecast elsewhere (i.e. Buller, Westland, Fiordland, inland Southland, Gisborne, Hawkes Bay, Bay of Plenty, Coromandel, Waikato, Waitomo and the Central Plateau).