ENSO and Sea Surface Temperatures
Transition to La Niña like conditions in the equatorial Pacific
Negative SST anomalies (-2°C) along the South American coast
Sea surface temperature (SST) conditions in the equatorial Pacific indicate a rapid shift towards a La Niña like pattern. These conditions are likely to last through the southern hemisphere winter.
The NINO3 SST anomaly was -0.4°C in May, and NINO4 has eased back to +0.3°C. The three month (March – May) means are about -0.1°C and +0.6°C for NINO3 and NINO4, respectively. The thermocline is elevated near the South American coast, with a -2.0°C anomaly in subsurface temperatures sloping towards the surface in the eastern equatorial Pacific. Suppressed convection is evident across the eastern equatorial Pacific and the trade winds are near normal strength east of the Dateline.
Recent significant Madden-Julian Oscillation (MJO) activity has occurred in the west (across the Maritime Continent), with zonal westerly wind anomalies west of the Dateline. The May SOI was -0.8, as a result of a recent strong pressure rise at Darwin.
A number of models indicate a short period of moderate La Niña conditions, followed by a return to neutral by the end of 2003.
Sea surface temperature anomalies (°C) for May 2003
Mean sea surface temperatures (°C) for May 2003
