El Niño/Southern Oscillation (ENSO)

The tropical Pacific ocean remained in a neutral state (neither El Niño nor La Niña) in November 2013.

The western Pacific ocean continues to be warmer than normal, and the central Pacific has slightly warmed up recently.

The NINO4 sea surface temperatures (SST) index (in the western Pacific) presents the largest anomalies at 0.5°C for November (up from 0.3°C in October). NINO 3 is close to 0 and NINO 3.4 is weakly positive at +0.16°C (was –0.17°C in October).

The large area of higher than normal SSTs in the Central east Pacific has shifted southwestard and is now centered around 40°S and 175°W , while cooler than normal SSTs have reappeared around French Polynesia (a situation similar to September).

The core of warmer than normal subsurface waters that was present at about 150m depth west of the Dateline has expanded towards the central Pacific.

The trade winds were intensified in the far western Pacific, and close to normal elsewhere.

The Intertropical Convergence Zone (ITCZ) was displaced south of its climatological position.

Rainfall within the South Pacific Convergence Zone (SPCZ) was mostly suppressed in the western Pacific (west of the Dateline) but intensified in the east.

The latest value for the TRMM ENSO index for the 30 days to 3 November is –0.83 (compared to –0.09 in October).

The SOI is currently slightly positive (+0.8).

The Madden – Julian Oscillation (MJO) was mostly inactive in the western Pacific in November. The MJO forecast for the next two weeks indicates intensified intra-seasonal convective activity over the maritime continent.

The consensus forecast from IRI / CPC indicates that neutral ENSO conditions are extremely likely to persist over the December 2013 – February 2014 period, with 96 % chance, versus 3 % for La Niña and only 1 % chance for El Niño.