Australia is facing a warmer than average winter across most of the country, according to the Bureau of Meteorology’s annual winter outlook.
It predicts higher than average minimum temperatures across Australia, with maximum temperatures in northern, south-eastern and south-western Australia also likely to be higher than average.
The bureau has forecast more winter rainfall than usual across northern and eastern Australia.
Dr Naomi Benger, a climatologist at the bureau, said above-average sea surface temperatures in the Indian Ocean are driving extra moisture over much of the country.
“Certainly, there are many farmers who would really appreciate that rainfall,” Benger said.
“In northern parts of the country, at this time of year, they have their dry season, which means it only takes very little rainfall to actually exceed their median.”
Despite the expected winter rainfall, according to the Bushfire and Natural Hazards Cooperative Research Centre’s winter outlook, significant vegetation growth in the Northern Territory – the result of a bumper wet season – may lead to above-normal fire risk in parts of the Top End.
Some parts of southern Australia will be drier than usual, including in southern Western Australia and western Tasmania, where neutral to dry conditions are expected.
This is consistent with data from the past two decades showing a trend towards drier conditions in autumn and early winter. “For southern Australia, we’ve seen a decrease around 10 to 20% in wet season rainfall – that’s April to October,” said Benger.
“Of course, some parts have seen very wet conditions [this autumn],” she said. New South Wales had its second-wettest March on record, with extreme rainfall and severe flooding.
Parts of western Victoria and the agricultural region of South Australia saw below-average rainfall for autumn, and may be headed for a dry winter.
Temperatures this past autumn have been the coolest across Australia since 2015.
But in winter, coastal areas in particular may experience days which are warmer than average, and higher-than-average night-time temperatures are also expected across most of the country.
The El Niño–Southern Oscillation – a long-term driver of climate – is neutral, and will likely remain that way throughout winter.
“There are large areas of Australia whose rainfall is influenced by the behaviour of the Indian Ocean,” said Benger. “The Indian Ocean is undergoing a lot of change at the moment,” she said, which may affect the accuracy of predicted rainfall in some regions.
The bureau based rainfall and temperature averages on observations made between 1990 and 2012.