Retrospective: December 2015-February 2016 Outlook

During December 2015 - February 2016, above normal pressure was forecast to the north of New Zealand, while below normal pressure was expected to the south of the country.  This circulation pattern was likely to be accompanied by anomalous westerly wind flows - a signature of El Niño conditions.

Actual pressures were higher than normal over the South Australian Bight and the Tasman Sea. Pressures were also slightly higher than normal to the east of New Zealand. This pressure set up resulted in a mixed flow anomaly.

Predicted air temperature: December 2015 - February 2016 temperatures were most likely to be near average for the north and east of the North Island as well as the east of the South Island.  Temperatures were about equally likely to be near average or below average for all remaining regions of the country.

Outcome: Actual seasonal temperatures were in fact above average for virtually the entire country. This was largely driven by warm February temperatures (2nd warmest February on record). Small pockets of near normal temperature could be found along the coasts of Gisborne, Hawke’s Bay, Canterbury and Southland.

Predicted rainfall: December 2015 - February 2016 rainfall was most likely to be below normal for the north and east of the North Island. Seasonal rainfall totals were about equally likely to be near normal or below normal for the west of the North Island as well as the north and east of the South Island.  Rainfall was equally likely to be near normal or above normal for the west of the South Island.

Outcome: Actual rainfall was below normal in Taranaki, Manawatu-Wangnaui, Hawke’s Bay, Wellington as well as parts of Gisborne, Waikato and Otago. Rainfall was above normal in parts of Tasman, Nelson, Marlborough and Northland and near normal elsewhere.

Weather station. [NIWA]