FARMERS in southeast Australia should enjoy the rain while it lasts, because the odds are moving towards a dry finish to the year.
The Bureau of Meteorology seasonal outlooks shows there is only a 25-40 per cent chance of exceeding the median rainfall for October to December across Victoria, Tasmania, southern NSW and southeast South Australia.
The odds are related to warm conditions in the Pacific and Indian oceans.
National Climate Centre senior climatologist Grant Beard said the pattern of warmer ocean temperatures across the Pacific was linked to an El Nino.
"The El Nino is not going completely to script," Mr Beard said. "It's not playing by the rules."
He said there was warm water right across the equatorial Pacific, whereas usually an El Nino coincided with cooler water in the western Pacific and around Australia.
Mr Beard said the Southern Oscillation Index, which measures air pressure differences between Darwin and Tahiti, had been bouncing around zero for a few months.
"Usually, it should be consistently negative for an El Nino," Mr Beard said.
"But the SOI has been positive, plus four, for the past 30 days."
He said the signals from the trade winds were inconsistent.
"We would expect the trade winds to be weaker than average with an El Nino, but we're getting inconsistent signals," Mr Beard said.
"It's a confusing mix of indicators," he said.
Mr Beard said southeast Australia could expect higher than average temperatures during the next three months.
"We would expect it to be warmer than the long-term average," he said.
Across Australia there is a mixed outlook for rain.
The bureau said the odds had shifted in favour - 60-75 per cent - of a wetter-than-normal season in western and central Western Australia.
But northwest WA looks headed for drier than normal conditions.
