Retrospective - November to January Outlook

Weak to moderate La Nina conditions were projected to continue through the early summer period (November 2011 to January 2012), with mean sea level pressures forecast to be near normal or above normal across New Zealand. Moderate La Nina conditions did indeed prevail through the season, with higher pressures than normal over the Tasman Sea and the southwest South Island, and near normal mean sea level pressures over the North Island. This circulation pattern brought more southerly winds than usual across the country, during the early summer period.

Predicted rainfall: Rainfalls are likely to be near normal in all regions of the country.

Outcome: Above normal rainfall fell over the majority of the North Island apart from parts of Northland, south Auckland, the Coromandel, eastern Bay of Plenty, the Gisborne District, parts of the central North Island and parts of the east coast south of Napier where normal rainfall was observed. For the South Island, above normal rainfall fell over the Tasman, Buller, Nelson and Marlborough districts as well as over south Canterbury. Below normal rainfall was observed in the south and west of the South Island and normal rainfall fell elsewhere. 

Predicted air temperature: Air temperatures are likely to be near average over the North Island and average or above average over the South Island.

Outcome: For most of the North Island average temperatures were observed, with the exception of parts of Northland, Waikato, Hawkes Bay, Manawatu, south Taranaki and eastern Wellington regions where below average temperatures occurred. Near average temperatures were observed for much of the South Island. However, below average temperatures occurred along the east coast of the South Island from South Canterbury to the Marlborough district and above average temperatures occurred over western Otago and Southland regions.