SEA SURFACE TEMPERATURE (SST)

La Niña conditions declined from strong to moderatestrength during March 2008 as negative sea surface temperature (SST) anomalies weakened across the central and eastcentral equatorial Pacific. The latest weekly SST values remain more than 1.0°C below average in areas between 160°E and 120°W. All of the NIÑO indices experienced warming during March, with only the westernmost NIÑO-4 and NIÑO-3.4 regions having values nearly 1.0°C below average. SSTs in the far eastern equatorial Pacific remained above average in association with a significant warming trend that began in mid-December. In the eastern equatorial Pacific, positive SST anomalies have been present near the South American coast since February. The latest weekly SST values are more than 1ºC above average between the South American coast and 110ºW. Subsurface warming in the central Pacific has led to a significant weakening of the cold anomalies in the upper 300m of the ocean. Despite this warming trend, the collective atmospheric and oceanic conditions continue to indicate an ongoing, but weaker, La Niña.

Graphic from NOAA's U.S. Climate Prediction Center