Farmers in Western NSW are being warned not to expect a wet summer despite the Bureau of Meteorology predicting a La Nina to occur.
The bureau has said there is a 70 per cent chance a La Nina period will begin in December, but while the climate pattern would normally bring above average rainfall, this one is likely be an exception.
The Indian Ocean's influence is tending to counter some of the typical La Nina characteristics, prompting the bureau to predict much of the country may actually get a warmer and drier than average summer.
BOM senior climatologist Felicity Gamble said it will likely mean an average summer for rainfall in Western NSW but temperatures are expected to be high.
“This year we’re unlikely to see a “typical” La Nina response – as if an event does occur, it’s likely to be weak and short-lived,” Ms Gamble said.
“As far as rainfall is concerned, current outlooks for the coming months suggest little shift towards a much wetter or much drier than average period.
“Both daytime and nighttime temperatures showing an increased chance of being warmer than average for Western NSW.”
Between 2010 and 2012, La Nina brought above average rainfall to the region, breaking droughts in many towns and giving some farmers their most productive seasons in years.
However sea-surface temperatures in the eastern Indian Ocean have been cooler than average, which "may be limiting the feed of moisture over Australia, and opposing more typical La Nina influences", the bureau says.
Dr Andrew Watkins, the manager of long range forecasts at the Bureau of Meteorology said he expects the bushfire risk for summer to remain unchanged despite the La Nina prediction.
“Typically a La Nina would result in a decrease to the risk over summer but this year because it is such a late event and the other opposing factors, we are saying it will remain warmer than normal,” Dr Watkins said.
“Unfortunately, this time the bushfire potential remains the same.”