Australia is most likely headed for an El Nino weather pattern, meaning hotter and drier conditions and greater risks of bushfires in the country's east.
The Bureau of Meteorology is forecasting a 70 per cent chance of El Nino occurring and on Tuesday officially raised its outlook from "watch" to "alert".
"What that means is we'll see an increased confidence that an El Nino will develop in the spring and even summer months," Bureau of Meteorology's senior meteorologist Dean Narramore said on Tuesday.
During El Nino, there is a higher chance of drier weather in eastern Australia and the southern two-thirds of the country are likely to be warmer than usual.
The upgrade from watch to alert was caused by a warming in the sea surface temperatures, which tipped over the threshold for El Nino classification, but atmospheric temperatures remain below that level, Mr Narramore said.Â
Bureau senior climatologist Catherine Ganter said climate models and indicators pointed to an El Nino, including warmer temperatures in the Pacific Ocean.
"While our El Nino alert criteria have been met, these changes will need to strengthen and sustain themselves over a longer period for us to consider an El Nino event," she said.
Earlier this year it was confirmed the sister weather pattern, La Nina, which brings wetter conditions to Australia's east, had ended after three years when the country experienced record floods.
El Nino occurs on average every three to five years but has not been experienced in Australia since 2016.
As well as less rainfall in eastern Australia, during El Nino the country can expect increased bushfire danger, increased risk of extreme heat, decreased alpine snow depths, a later start to the northern wet season and reduced tropical cyclone numbers.
"We know from the historical record that bushfire events are more likely during periods of El Nino, whereas floods and cyclones are less likely (but can still happen)," said Dr Tom Mortlock, senior analyst at Aon and adjunct fellow at UNSW Climate Change Research Centre.
"The concern now is that - with the long absence of El Nino and back to back La Ninas - the landscape is preconditioned for bushfire with significant fuel growth occurring."
Ms Ganter said it was very likely the tropical Pacific Ocean temperatures would reach El Nino levels during winter.
"The bureau's long-range winter forecast is for drier and warmer conditions across almost all of Australia and the climate conditions in the Pacific Ocean are already factored into our forecasts," she said.
"The long-range forecast for winter also shows an increased chance of below average rainfall for almost all of Australia and the move to El Nino alert does not change this forecast."