Sept. 10, 2004 — NOAA declared today that El Niño is back but this time around in a weaker state. "El Niño conditions have developed in the tropical Pacific and are expected to last through early 2005," said Jim Laver, director of the NOAA Climate Prediction Center. "At this time it is not clear what, if any, impacts this event will have on ocean temperatures in the classical El Niño region along the west coast of South America and on temperature and precipitation in the United States." (Click the NOAA satellite image for larger view of El Niño taken Sept. 7, 2004. The warm sea surface temperatures in the eastern Pacific Ocean are represented in red. Click here for high resolution version, which is a large file. Please credit “NOAA.”)
Impacts depend on a variety of factors, such as the intensity and extent of the warming in the tropical Pacific. NOAA will continue to monitor the situation in the tropical Pacific and will provide more detailed information on possible impacts due to this event in coming months.
In the release of the El Niño Diagnostic Discussion, the NOAA Climate Prediction Center scientists noted that sea surface temperatures (SSTs) were more than 0.5 degrees C above average in the central and western equatorial Pacific during August 2004. By early September, positive SST departures greater than 0.5 degrees C (~1 degree F) were found between 160 E and 120W, with departures greater than 1 degree C extending from 170 E eastward to 140 W.
"The increase and eastward expansion of warmth in the central equatorial Pacific during July through August indicate the early stages of a warm (El Niño) episode," said Vernon Kousky, NOAA's lead ENSO forecaster. He added, "Through the end of August conditions were not yet indicative of a basin-wide El Niño, particularly due to the presence of below normal sea-surface temperatures in the far eastern equatorial Pacific near the South American coast." The lack of basin-wide warming indicates that this El Niño is likely to be much weaker than the 1997-1998 event.
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http://www.noaanews.noaa.gov/stories2004/s2317.htm