Global setting: January 2016

Strong El Niño conditions continued in the tropical Pacific during January 2016. Sea surface temperature anomalies still exceed +2oC in the central and eastern Pacific, but have weakened slightly from the peak values in November-December 2015.

The sub-surface ocean temperature anomalies in the eastern Pacific have decreased further since December, and are now about +4oC at 75-100m depth near 120oW, compared to peak values of about +7oC in November 2015. Conversely, the Southern Oscillation Index strengthened to about -2.0 for the month of January.

International guidance indicates that El Niño conditions will continue (96% probability) over the next three months (February – April 2016) and will rapidly decay thereafter, with a return to normal conditions or a transition to La Niña conditions by August – October 2016.

For February - April 2016, above normal pressure is forecast to the north of New Zealand, while below normal pressure is expected to the south of the country.  This circulation pattern is likely to be accompanied by anomalous westerly wind flows – a signature consistent with El Niño.

Sea Surface Temperatures

Sea surface temperatures around New Zealand are forecast to be near average to the west and below average to the east of the country

Differences from average global sea surface temperatures for 10 January - 06 February 2016. Map courtesy of NOAA Climate Diagnostics Centre (http://www.esrl.noaa.gov/psd/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: January SOI -1.9; November to January average -1.0.
Differences from average January surface temperatures in the seas around New Zealand.