Retrospective - December to February Outlook

The NIWA National Climate Centre's outlook for summer, December 2011 to February 2012, correctly indicated La Niña conditions, with weaker than normal westerlies over the North Island. East to northeast wind anomalies in fact did prevailed over the North Island, as per forecast.

Predicted rainfall: Summer rainfall totals are likely to be below normal on the West Coast, and normal or below normal across the remainder of the South Island, as well as in the southwest of the North Island. Near normal seasonal rainfall is likely for the eastern North Island. For the northern North Island, summer rainfall is equally likely to be normal or above normal.

Outcome: Summer rainfall totals were correctly forecast to be below normal on the West Coast, and wetter than normal was correctly indicated for north of Taupo. Observations showed near normal summer rainfall for eastern parts of Northland, Gisborne, south Hawkes Bay, North Canterbury, Christchurch, parts of Otago and parts of Southland. Elsewhere, it was wetter than forecast, with above normal summer rainfall totals observed.

Predicted air temperature: Air temperatures are likely to be above average on the West Coast of the South Island, and near average or above average across the remainder of the country. Sea surface temperatures are likely to remain above average to the northeast of the North Island during summer, but near average elsewhere about the New Zealand region.

Outcome: Seasonal temperatures were correctly predicted to be above average on the West Coast of the South Island. Observations showed near average summer temperatures for Northland, Auckland, Taranaki, and central Otago, whilst below average summer temperatures were experienced elsewhere (where near average or above average summer temperatures were indicated).