Last week the U.S. Climate Prediction Center said La Nina has returned, but the Australian Bureau of Meteorology this morning said neutral conditions persist in the equatorial Pacific Ocean, though a return to La Nina toward the end of the year cannot be ruled out.
"The majority of international climate model forecasts of ENSO predict that neutral conditions are likely to continue into the southern spring (Sept-Nov.). While no models suggest El Niño conditions are likely, half of the models predict further cooling over the coming season and into the southern summer (Dec-Feb.)," says the Bureau.
Aussie scientists point out it’s worth noting that since 1900, about half of all La Niña events re-emerged in the second year. Further cooling of the central Pacific Ocean coupled with persistent positive SOI values in the next few months would further increase the chance of a La Niña event at the end of 2011.
Juli says: It's not uncommon for U.S. and Aussie weather bureaus to disagree on the beginning/end of an ENSO event such as La Nina or El Nino.