Global setting: November 2015

The latest monthly sea surface temperature anomalies exceed +2oC in the central and eastern Pacific.

Sub-surface temperature anomalies in the eastern Pacific increased over the last month (November 2015) and exceed +7oC at 75-100m depth near 120oW.

The SOI showed a – temporary – weakening in November (November value is -0.6), but overall the atmosphere remains well coupled with the ocean. In particular, strong westerly wind anomalies (weaker easterly trade-winds) dominate the western and central Pacific. Convection and rainfall are also much more intense than normal in the central and eastern Pacific, while overall large-scale convection was reduced over the Maritime Continent.

International guidance indicates that El Niño will continue (100% probability) over the next three months. Models have the event continuing through the following season, March-May 2016, and the majority predicts a rapid return to ENSO-neutral conditions in June-August 2016. By some measures, the current event is on par with the 1997/98 El Niño (the strongest since 1950).

For December 2015 - February 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 of El Niño conditions.

Sea Surface Temperatures

Ocean models suggest that waters will remain cooler than normal to the east of the South Island.

Differences from average global sea surface temperatures for 1-28 November 2015. 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: November SOI -0.6; September to November average -1.5.
Differences from average November surface temperatures in the seas around New Zealand.