El Niño/La Niña Update (June 2009)

Rapid changes in oceanic and atmospheric conditions in the tropical Pacific in 

recent months, and an increasing number of computer model predictions, are now 

pointing to a substantial likelihood of an El Niño event in the second half of 2009. 

However, surface climate conditions in the tropical Pacific are overall still 

considered near-neutral at this time. The situation therefore warrants especially 

careful monitoring over the next couple of months. Current assessments suggest 

that by the end of the third quarter of 2009, El Niño and near-neutral conditions are 

considered about equally likely outcomes across the tropical Pacific, with La Niña 

very unlikely. To place this in better context, El Niño typically occurs once every 

4-5 years, so the current assessments translate to a substantially elevated risk of 

an El Niño developing later this year. This information, when expressed in terms of 

expected climate patterns, will be relevant to many climate-related risk 

management systems, and users are encouraged to seek detailed interpretations 

for their locations and sectors.