La Niña possible within the next 2-3 months

Created by doina. Last modified on 2007-05-14 11:32:24
Topic: Weather

The pattern of anomalous sea surface temperatures (SSTs) during April 2007 was consistent with ENSO-neutral conditions in the tropical Pacific, with average to slightly below average SSTs extending from the date line to the west coast of South America.

The upper-ocean heat content (average temperature departures in the upper 300 m of the ocean) remained below average across the central and east-central equatorial Pacific, with temperatures at thermocline depth generally 2°-5°C below average.

Consistent with the surface and sub-surface ocean temperature patterns, stronger than-average low-level easterly winds persisted over the central equatorial Pacific. Also, convection was enhanced over the western equatorial Pacific and suppressed east of the date line. Collectively, these atmospheric and oceanic conditions continue to indicate the possibility that La Niña conditions will develop over the next 2-3 months.

Some forecast models, especially the NCEP Climate Forecast System (CFS), predict a rapid transition to La Niña during May-July 2007. However, for the past few months the CFS forecasts have been predicting a stronger and more rapid cooling than has actually occurred. Historically, the next couple of months are a critical time period for the possible emergence of La Niña.

Oceanic and atmospheric conditions are updated weekly at NOAA Climate Prediction Center

Forecasts for the evolution of El Niño/La Niña are updated monthly in the Forecast Forum section of CPC's Climate Diagnostics Bulletin.