Retrospective: November 2015-January 2016 Outlook

During November 2015 - January 2016, above normal pressure was forecast to the north and west 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 west-southwesterly wind flows - a signature of El Niño conditions.

Actual pressures were slightly higher than normal in the Tasman Sea and extended over New Zealand. Lower than normal pressure was present to the south of the country. This pressure set-up lead to more south-westerlies than normal over the South Island and more south-easterlies than normal over the North Island.

Predicted air temperature: November 2015 – January 2016 temperatures were equally likely to be average or below average for the north and east of the North Island, and most likely to be near average for the east of the North Island and north of the South Island. Below average temperatures were most likely for the west and east of the South Island. 

Outcome: Actual temperatures were near average for the majority of New Zealand. Slightly warmer than normal temperatures occurred in Whangarei, the Far North and the Taupo district.

Predicted rainfall: November 2015 – January 2016 rainfall was most likely to be below normal in the north and east of the North Island, but equally likely to be near normal or above normal in the west of the South Island.  Near normal rainfall was the most likely outcome for the west of the North Island and north of the South Island.  There was low confidence in seasonal rainfall in coastal Canterbury and east Otago.

Outcome: Actual rainfall was largely near normal for the north and east of both the North and South Island as well as Westland and coastal Southland. Rainfall was below normal elsewhere.

Weather station. [NIWA]