Neutral conditions (neither El Niño nor La Niña) continue in the tropical Pacific. Model forecasts and expert opinion suggest that neutral conditions are likely to be maintained through the boreal autumn of 2013 and winter 2013-14. Two or more consecutive years of neutral conditions have been observed in the past and the situation is not unusual. National Meteorological and Hydrological Services and other agencies will continue to monitor the conditions over the Pacific and provide outlooks to assess the most likely state of the climate through the remainder of 2013 and into early 2014.
Since the boreal spring of 2012, El Niño-Southern Oscillation (ENSO) indicators in the tropical Pacific (e.g., tropical Pacific sea surface temperatures, sea level pressure, cloudiness and trade winds) have generally been at neutral levels, indicating that neither El Niño nor La Niña conditions have been present. Since May 2013, sea surface temperatures have been well below average in the far eastern tropical Pacific, only recently returning toward normal. However, these cold sea surface temperatures have been positioned too far to the east to be considered indicative of a basin-wide La Niña episode, even though they caused some minor impacts over local climate conditions in western parts of South America.
The latest outlooks from international climate models and expert opinion suggest that sea surface temperatures and atmospheric anomalies associated with El Niño or La Niña are most likely to remain neutral through the end of 2013 and into early 2014. Less than one-fifth of the models surveyed predict weak La Niña conditions to develop during the October to December period, and likewise less than one-fifth predict weak El Niño development during that period and into the first quarter of 2014. Therefore, while there is a very slight chance for La Niña or El Niño development during the next one or two seasons, neutral ENSO conditions are considered by far the most likely scenario. >> full report