Some climate experts fear the El Nino forecast is too hasty

Most say it just too early to tell.

Dr Nandini Ramesh is a senior research scientist with CSIRO and the University of Sydney who says predicting how the Pacific Ocean and atmosphere will evolve from this time of year (March-May) is notoriously difficult.

The Bureau of Meteorology this week announced the La Nina was officially over and it was now on El Nino watch.

"The tropical Pacific Ocean is now in a neutral phase - neither La Nina nor El Nino but there are signs of an El Nino forming later in the year," the bureau said.

The bureau also said there have been 27 El Nino years in Australia since 1900 and just over half of them resulted in a widespread winter-spring drought.

Dr Nandini Ramesh said a similar El Nino forecast was made in 2014, pointing to an El Nino developing in the latter half of 2014.

"Instead, those early signs fizzled out, and an El Nino only developed a year later in late 2015. So while most forecast models now predict an upcoming El Nino, I wouldn't place any bets just yet," Dr Ramesh said.

He said the Pacific region "is very responsive during this season to sudden changes in, among other factors, wind speeds over the western Pacific."

MORE READING: Fake chicken nuggets fail food standards

Dr Milton Speer, a Visiting Fellow in the School of Mathematical and Physical Sciences at The University of Technology, Sydney, also weighed in saying the months of April/May in southeast Australia have seen significantly below average rainfall since the 1990s because of changes in the jet stream.

Dr Tom Mortlock, a senior analyst at financial services firm Aon and Adjunct Fellow at the UNSW Climate Change Research Centre, said the rare triple-dip La Nina was only the fourth since 1900 and the first in 22 years.

Dr Mortlock said research by Aon and partners Climalab suggests the triple-dip La Nina may have tipped the Pacific ocean circulation into a long-term El Nino like state that could now persist for the coming decade.

Dr Kimberley Reid, an atmospheric scientist from the ARC Centre of Excellence for Climate Extremes at Monash University, said the Earth's climate is like a pendulum and it was not unusual to swing into an El Nino after a La Nina.

The bureau said the 50pc chance of El Nino is about twice the normal likelihood.

"El Nino watch is not a guarantee that El Nino will occur, but it is an indication that some of the typical precursors are currently observed."