Global Setting – August 2013

The equatorial Pacific Ocean as a whole remains in a neutral state (neither El Niño nor La Niña), although colder than normal (La Niña-like) sea temperatures persist in a shallow surface layer in the eastern equatorial Pacific. International guidance indicates that ENSO-neutral is the most likely outcome for the next three months (September–November). For the New Zealand region, higher pressures than normal are forecast south of the country, while lower pressures than normal are expected from Queensland eastwards. This circulation pattern is expected to produce more northerlies or north-westerlies affecting the North Island, and a weaker than normal westerly flow over the South Island. 

Sea Surface Temperature 

Sea surface temperatures are forecast to be above the climatological average for the coming three months around New Zealand. 

Differences from average global sea surface temperatures for 4th of August to 31st of August 2013. 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 -0.2; June to August average +0.6.