ENSO Quick Look
IRI ENSO Update / Forecast
Technical ENSO Update
IRI Probabilistic ENSO Forecast
ENSO Prediction Plume
Monthly archive

ENSO Update

16 April 2008

Summary

La Niña conditions have weakened in the equatorial Pacific. Below-average sea surface temperatures (SSTs) still exist across central equatorial Pacific, but they have been trending toward neutral since February 2008. There is a 60% probability of maintaining La Niña conditions over the coming season.

General Discussion

The La Niña conditions that have been in place since August 2007 appear to have peaked in February 2008, and are now trending towards ENSO-neutral conditions. The below-average SSTs are weakening in the central and eastern equatorial Pacific, while above-average SSTs exist in the far eastern Pacific. The equatorial heat content is increasing. Also, the Southern Oscillation index has been decreasing, suggesting a weakening of the atmospheric manifestation of La Niña. On the other hand the remaining easterly wind anomalies and below-normal temperatures may be enough to retain La Niña classification over the next month or two.

Out of a large set of dynamical and statistical forecast models, most models indicate continued weakening of the La Niña conditions through 2008, most of them reaching ENSO-neutral SSTs by mid-2008. Overall, based on model forecasts and current observations of the ocean surface and subsurface, the probability of a La Niña is estimated at 60% for the Apr-May-Jun season in progress. The probability of returning to ENSO-neutral conditions increases to the climatological value of 50% by mid-2008.

Note 1 - Only models that produce a new ENSO forecast every month are included in the above statement.

Top of Page