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ENSO
Quick Look
IRI ENSO Update / Forecast Technical ENSO Update Summary of Model Forecasts Monthly archive ENSO Update19 April 2005SummarySea surface temperatures in the eastern and central equatorial Pacific are currently near-normal or ENSO-neutral, although they remain above-average throughout much of the equatorial Pacific. Based on the latest observations and forecasts, it is 65% likely that neutral conditions will prevail over the Apr-May-Jun 2005 season.General DiscussionDuring March 2005, sea surface temperatures (SSTs) were within the range of near-normal conditions. Although the SST anomalies in the central Pacific are currently classified as near-normal, the anomalies were above-average and more than 0.5 degree C warmer than average along the equator west of 160W. During March, the trade winds near the equator remained close to their average strength for this time of year. However, large positive temperature anomalies were observed in the central equatorial ocean as a result of strong westerly wind anomalies in the western/central Pacific during February 2005. The subsurface warm anomaly has now reached the South American coast and is beginning to warm SSTs in the eastern equatorial Pacific. Out of a large set of dynamical and statistical forecast models, approximately 40% predict sea surface temperatures at weak El Niño levels for the April to June period in the central Pacific. Overall, based on model forecasts and current observations of the ocean surface and subsurface, the chances for returning to El Niño conditions are approximately 35% through June 2005, increasing very slightly thereafter. The likelihood of maintaining neutral conditions is approximately 65% through June 2005, and remains the most lkely scenario through the end of 2005. The probability of a La Niña developing between now and June 2005 is near zero, rising to 5% thereafter.Note 1 - Only models that produce a new ENSO forecast every month are included in the above statement.
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