New Zealand Climate Update 150 – December 2011

What happened in November, how our climate outlook for the previous three months turned out, global and local sea temperatures, and our outlook for December to February. 

Current Climate - November 2011

Much stronger than normal southwest winds affected New Zealand during November 2011, squeezed between higher than normal pressures over the Tasman Sea and lower pressures to the southeast of the country. The southwesterly winds produced a cooler than usual month along the southern and western coastline of the South Island, but a warmer than average month in the sheltered northeast coast of the North Island. These winds also produced an extremely dry month for regions north of Taupo, but in contrast it was an unsettled and very wet month across much of the South Island. 

Outlook - December 2011 to February 2012

A weak to moderate La Niña is in place in the tropical Pacific and should persist into early 2012. Mean sea level pressures for summer as a whole are likely to be above normal across the South Island and southern North Island, but below average to the north of New Zealand. Temperatures are likely to be above average for the West Coast, and average or above average in all other regions. Summer rainfall is likely to be near normal for the north of the North Island, below normal for the West Coast, and normal or below normal elsewhere. 

Retrospective - September to November Outlook

Neutral ENSO conditions were predicted in the tropical Pacific Ocean for spring 2011, although in actual fact a weak to moderate La Nina had redeveloped by season end. Mean sea level pressures were (correctly) projected to be above normal across much of New Zealand, although the expectation of weaker westerly circulation than normal over the country was not (a southwest anomaly affected New Zealand during spring, helped along by the extremely windy November).