ENSO and Sea Surface Temperatures
SOI negative for second month
Equatorial Pacific about 1.0°C warmer than normal
The tropical Pacific remains near neutral, with mixed warming and cooling signals and a fluctuating SOI over the past few months. July equatorial SST anomalies were below average near the South American coast, but above normal in the remainder of the equatorial Pacific east of the Date Line, and more than 1.0°C above normal near the Date Line.
The NINO3 SST anomaly was +0.0°C for July (+0.1°C in June), and NINO4 was +1.0°C (+0.6°C in June). May to July SST means for NINO3 and 4 were about +0.1°C and +0.7°C, respectively. Subsurface temperatures show quite a strong positive anomaly (exceeding +3.0°C) at 150 m depth just east of the Date Line, which has developed following a strong westerly wind-burst at 160°E in June.
July averaged OLR anomalies show convection was below normal for the month around Indonesia and northern Australia, and along most of the Pacific Equatorial belt.
The majority of models indicate neutral conditions to the end of 2004, although NINO3 SST anomalies remain positive. Four of the available models indicate sufficient warming in the NINO3 region to qualify as El Niño conditions by early 2005. The chances of an ENSO event evolving this year have increased significantly, but neutral conditions on the warmer side are more likely to continue for the immediate three-months (August-September).
Sea surface temperature anomalies (°C) for July 2004
Mean sea surface temperatures (°C) for July 2004
