ENSO and Sea Surface Temperatures
The tropical Pacific Ocean remains in a weak El Niño state. The NINO3.4 average anomaly was about +0.8°C in December, similar to the October/November values. Subsurface temperature anomalies are positive (up to +3°C) in the top 100 m in the eastern Equatorial Pacific. East-west wind anomalies are positive in the central Pacific, after a period of strong westerly anomalies in the west in early December.
Outgoing longwave radiation and rainfall anomalies show enhanced convection west of the Date Line, especially south of the Equator, and suppressed convection over Indonesia and northern Australia. The Southern Oscillation Index (SOI) remained at -1.1 in December (three-month October to December mean -0.9), indicative of a continued weak El Niño event.
Most available global climate models indicate weak El Niño conditions through the first three months of 2005, but almost all ease to neutral conditions by early winter. All available models indicate neutral conditions by July-September 2005.
The latest US National Center for Environmental Prediction/Climate Prediction Center statement is for weak El Niño conditions continuing for the next three months. The International Research Institute for Climate Prediction summary describes the present situation as a weak El Niño state, and gives a 75% chance of weak El Niño conditions continuing through March 2005.
Sea surface temperature anomalies (°C) for December 2004
Mean sea surface temperatures (°C) for December 2004
