Retrospective: February-April 2016 Outlook

For February - April 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 consistent with El Niño.

Actual pressures were much higher than normal over and to the east of New Zealand. This pressure set-up resulted in north-easterly flow anomalies over the whole of New Zealand.

Predicted air temperature: February - April 2016 temperatures were most likely to be above average for the north and west of the North Island.  Temperatures were about equally likely to be near average or above average for all remaining regions of the country.

Outcome: Actual seasonal temperatures were above average for the entire country. Temperature anomalies exceed 2°C in parts of the central and southern North Island as well as the central and eastern South Island.

Predicted rainfall: February - April 2016 rainfall was about equally likely to be below normal or in the normal range for the north and east of the North Island and for the east of the South Island. Seasonal rainfall totals were most likely to be near normal for west of the North Island and for the north and west of the South Island.

Outcome: Actual rainfall was normal in the north of the North Island, north of the South Island, and west of the South Island. However, pockets of above-normal rainfall were found in the Far North, the Coromandel Peninsula, Tasman, Nelson, Westland and Fiordland. Meanwhile, rainfall was below normal in the west of the North Island, east of the North Island, and east of the South Island. Rainfall anomalies were especially extraordinary in parts of Carterton, where less than 20% of normal rainfall fell.

Weather station. [NIWA]