Roger Stone, professor in climatology at the University of Southern Queensland, says that the forecast for the start of winter looks promising for average or above rainfall for much of Queensland, the bad news is that the early signs point to a return of an El Nino weather pattern come spring.

"The SOI (Southern Oscillation Index) is falling quite rapidly at the moment," he said (see image).

According to The Weather Company, which provides forecasting information on FarmOnline, the SOI is calculated from the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin.

A strongly and consistently positive SOI pattern (e.g. consistently above about +6 over a two month period) is related to a high probability of above the long-term average (median) rainfall for many areas of Australia, especially areas of eastern Australia (including northern Tasmania).

But it says a 'deep' and consistently negative SOI pattern (less than about minus 6 over a two-month period, with little change over that period) is related to a high probability of below median rainfall for many areas of Australia at certain times of the year.

Prof Stone says on current trends climate modelling was forecasting a strong chance of a return of the El Nino come spring.

He said there has been a long-term trend of declining rainfall for much of Queensland, but the State's rainfall patterns were highly variable and changing.

"It's not all doom and gloom," Prof Stone said. "Summer rainfall seems far more reliable with the forecasts for the future, but it's the winter rainfall that seems much more variable.

"But none of this information has any value unless it changes management decisions [on farm]."

Prof Stone said climate change, while presenting a number of challenges to farmers, also presented opportunities in the form of new cereal crop varieties that can thrive in hotter and drier conditions thus allowing farmers to continue to operate profitably.