SEA SURFACE TEMPERATURE (SST)

Sea surface temperatures (SSTs) returned to near-average across the central and east-central equatorial Pacific in June 2008, marking a shift from La Niña to ENSO-neutral conditions. Since February 2008, negative SST anomalies have weakened in the central equatorial Pacific. From June to early July 2008, an area of positive anomalies increased in the eastern equatorial Pacific and expanded westward. Over the last month, the change in SST departures was positive across much of the central and east-central equatorial Pacific. The latest weekly SST index was -0.3°C in the Niño-4 region, 0.1°C in the Niño-3.4 region, 0.5°C in the Niño-3 region and +0.6°C in the Niño 1+2 region. The subsurface oceanic heat content (average temperatures in the upper 300m of the ocean), and patterns of subsurface temperature anomalies also reflect the transition to ENSO-neutral conditions. Similar to past transitions, La Niña continues to linger in the atmospheric circulation pattern, but with diminishing strength.

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