THE AUSTRALIAN farming community received unwelcome news from the Bureau of Meteorology (BOM) which this week announced the likelihood of an El Nino is now double that of an average year.
The BOM has raised its El Nino outlook status to watch, meaning that an El Nino event is now twice as likely as normal.
The El Niño–Southern Oscillation (ENSO) index remains neutral, however, recent warming in the tropical Pacific Ocean means the chance of El Niño forming in spring has increased according to the BOM.
Of note has been the warming of sea surface temperatures in the eastern Pacific since April and waters below the surface of the tropical Pacific are now warmer than average—a common precursor to El Niño.
With the dry start to the winter cropping season in eastern Australia, the threat of an El Nino, correlated with drier than average conditions over much of Australia’s cropping belt, will mean farmers yet to finish plants will now reconsider whether it is worth the risk.
Of the international models used by the BOM five of eight models indicate the ocean warmth is likely to reach El Niño thresholds in the southern hemisphere spring, while a sixth model falls just short.
This comes after the BOM put out a climate outlook for winter forecasting markedly lower than average chances of reaching average rainfall for much of the eastern cropping belt, not due to El Nino but because of high pressure ridges stopping low pressure troughs hitting landfall.
On the topic of high pressure ridges, BOM climatologist Andrew Watkins said May had seen an enormous high pressure anomaly.
“May saw the Australian mean sea level pressure difference from normal almost off the scale in terms of high pressure,” he said.
“Incredibly high pressure just blocked the cold fronts from the mainland and kept the skies clear and was a key driver in the well below average rainfall in many regions.”