Pacific ENSO Update

3rd Quarter, 2007 Vol. 13 No. 3

SEA SURFACE TEMPERATURE (SST)

Sea surface temperatures (SST) in the equatorial eastern Pacific have been cooler than average since January 2007. SST anomalies through mid-July were more than 1ºC below average in areas between 110ºW and the South American coast, and more than 0.5ºC above average in portions of the western Pacific. Equatorial sub-surface temperatures have remained mostly below average in the region east of the date line since May, while weak positive sub-surface temperature departures have extended from the western to the central Pacific. Recently, the magnitude of the negative subsurface temperature anomalies have increased slightly in the eastern and central Pacific, with a majority of the statistical and coupled model forecasts indicating that SSTs will continue to cool during the next several months. Therefore, ENSO-neutral conditions are likely to continue through the next 1-3 months, with a 50% possibility of La Niña conditions developing during the boreal autumn months.