Borderline El Niño conditions are present in the tropical Pacific, and a weak short-lived El Niño is predicted for the spring and summer periods. However, the seasonal forecast models do not yet show any sign of the enhanced southwesterly and westerly airflow over New Zealand that is usually associated with El Niño events. Over the spring period (September-November), higher than normal pressures are expected in the south Tasman and over southern New Zealand, along with lower pressures to the north of the North Island and weaker than normal westerlies over the country.
Sea surface temperatures
Sea temperatures around New Zealand are likely to be near normal for the season as a whole.
Differences from average global sea surface temperatures for 5th August to 1st September 2012. Map courtesy of NOAA Climate Diagnostics Centre (http://www.cdc.noaa.gov/map/images/sst/sst.anom.month.gif).
Monthly values of the Southern Oscillation Index (SOI), a measure of changes in atmospheric pressures across the Pacific, and the 3-month mean (black line). SOI mean values: August SOI -0.7; June to August average -0.7.
Differences from normal August surface temperatures in the seas around New Zealand.