Global setting & climate outlook

Global setting

El Niño-Southern Oscillation remains neutral

Difference from average global SST (click to enlarge).

Monthly SOI values (click to enlarge).

The tropical Pacific Ocean is in a neutral state with some features of weak La Niña conditions. Neutral conditions are expected to prevail into autumn 2006.

The SOI was near neutral in December (-0.1), with the 3-month October to December average at +0.2. The equatorial trade winds have strengthened near the Date Line.

Normal cyclone activity is expected through to April 2006. For New Zealand, this means a 70% chance of a cyclone passing near the country, with Northland and Gisborne being most at risk. The risk is greatest after the end of January.

Sea surface temperatures (SST) around New Zealand

New Zealand SST (click to enlarge).

The New Zealand average difference from the historical normal SST was about +0.8 °C for December, and +0.6 °C for the October to December average. Surface waters remained warmer than normal over the Tasman Sea and around the New Zealand coast.

Sea surface temperatures around New Zealand are likely to remain above average through to March 2006.

Outlook for January 2006 to March 2006

Regional outlook (click to enlarge).

Circulation patterns for late summer, January to March, favour slightly lower than normal pressures to the northeast. Air temperatures are expected to be above average in most regions of New Zealand.

Rainfalls are likely to be normal or above normal in the north and east of the North Island, normal or below normal in the east of the South Island, and near normal elsewhere. Soil moisture levels and river flows are expected to be normal for the North Island, and normal or below normal in the South Island.