New Zealand Climate Update 154 – April 2012

What happened in March, how our climate outlook for the previous three months turned out, global and local sea temperatures, and our outlook for April to June. 

Current Climate - March 2012

March was characterised by higher pressures than usual to the east of the Chatham Islands, and more lows than normal to the north of the North Island.  This produced more easterly winds than usual over the country.  The frequent easterly winds resulted in an extremely cool March for eastern areas of both Islands, and produced wetter conditions for many areas of the North Island and some eastern South Island regions.  It was also much cloudier than usual for the northeast of the North Island, as well as the northern South Island.

Outlook - April to June 2012

La Niña conditions are dissipating and a return to ENSO-neutral conditions is imminent. Lower pressures than normal are expected to the north of the country, with more anticyclonic conditions over and east of southern New Zealand. Seas around New Zealand are likely to remain slightly cooler than usual during late autumn.  Seasonal temperatures are likely to be average or above average in the west, south and east of the South Island, and near average elsewhere. Late autumn rainfall is likely to be normal or above normal in the north and east of the North Island, and near normal in all other regions.

Retrospective - January to March Outlook

A moderate La Niña was expected to persist over the January to March season – this was indeed the case with a 3-month SOI of around +0.5.  Mean sea level pressures were accurately forecast – these were projected to be above normal across the South Island, but below average to the north of New Zealand.  More north-easterly air flows than normal over the North Island were forecast; more frequent easterly winds were observed.