El Niño / La Niña Forecast

The latest assessment of sea surface temperatures in the tropical Pacific by the Climate Prediction Center indicates that El Niño conditions are expected to continue through the upcoming Winter and into Spring 2007. This forecast is based on predictions from the latest NCEP Climate Forecast System (CFS), first image below, as well as from more than two-thirds of the other statistical and coupled model predictions, second image below.

In order to be considered an El Niño/La Niña episode the sea surface temperature anomalies in the Niño 3.4 region have to at least meet the criteria listed below, and then remain at or above/below these levels for at least five consecutive months to be considered an El Niño/La Niña event.

El Niño = SST anomaly greater than or equal to +0.5 degrees C

Neutral = SST anomaly between -0.5 and +0.5 degrees C

La Niña = SST anomaly lesser than or equal to -0.5 degrees C

A more defined definition of El Niño, although not totally etched in stone is listed below.

Strong El Niño = SST anomaly greater than or equal to +2.0 degrees C

Moderate El Niño = SST anomaly between +1.0 and +1.9 degrees C

Weak El Niño = SST anomaly between +0.5 and +0.9 degrees C

Therefore, using this criteria, it can be seen in the images below that weak El Niño conditions are expected to continue this Winter with neutral conditions returning this Spring.