| ||
|
ENSO Quick Look IRI ENSO Update / Forecast Technical ENSO Update Summary of Model Forecasts Monthly archive ENSO Update17 March 2005SummarySea surface temperatures in the east-central equatorial Pacific have returned to near-normal or ENSO-neutral conditions, 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 Mar-Apr-May 2005 season.General DiscussionDuring February 2005, sea surface temperatures (SSTs) returned to near-normal conditions following the weak El Niño conditions observed in the east-central tropical Pacific since late July 2004. Although the SST anomalies in the central Pacific are currently classified as near-normal, the anomalies remain about 0.5 degree C above average along the equator west of 160W, increasing to over 1 degree C near the dateline. Also during February, persistent westerly winds in the central/western Pacific created anomalies in the sub-surface ocean that could potentially lead to a re-warming of the central/eastern equatorial Pacific over the next month or two. Out of a large set of dynamical and statistical forecast models, approximately 30% predict sea surface temperatures at weak El Niño levels for the March to May 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 May 2005, increasing slightly thereafter. The likelihood of maintaining neutral conditions is approximately 65% through May 2005, returning to the climatological likelihood (i.e. 50% probability) by August 2005. The probability of a La Niña developing between now and May 2005 is near zero, rising slightly thereafter but to a much lower level than the climatological likelihood of 25%, even in the second half of 2005.Note 1 - Only models that produce a new ENSO forecast every month are included in the above statement.
|
