Retrospective: October-December 2016 Outlook

For October – December, the circulation pattern expected for New Zealand was broadly consistent with a typical La Niña signature: higher pressure than normal was forecast to the south and southeast of the country, while lower pressures than normal were forecast to the north of the New Zealand.

These pressure anomalies were likely to be accompanied with easterly quarter flow anomalies. Actual pressures were lower than normal over New Zealand and to the southeast of the country. This pressure set up resulted in more westerly winds than normal. 

Predicted air temperature: October-December temperatures were expected to be above average for the whole country.

Outcome: Actual seasonal temperatures were near average for the majority of New Zealand. Small pockets of above average temperature were found in the Hawke’s Bay and Christchurch regions as well as the district of Tararua.

Predicted rainfall: October-December rainfall totals were about equally likely to be near normal or above normal in the North Island.  Seasonal rainfall totals were most likely to be in the near normal range in the north of the South Island. In the east and west of the South Island, rainfall was about equally likely to be near normal or below normal.

Outcome: Actual rainfall was below normal in Northland and parts of Gisborne, Hawke’s Bay, and eastern Manawatu-Wanganui. Conversely, rainfall was above normal in Tasman and Nelson as well as parts of Marlborough, Otago and the West Coast.