Australians to expect unusually warm and dry winter conditions

Australians have been warned to expected unusual conditions this winter as two major climate drivers are expected to occur concurrently.

Australians have been warned to expected unusual conditions this winter as two major climate drivers are expected to occur concurrently.

Australians can expect “abnormal” conditions throughout the winter season as two systems work together to bring unseasonably dry weather.

While it was too soon to say for sure if an El Niño – bringing reduced rainfall and warmer temperatures – would occur during the winter, international climate models have indicated it was “very likely”.

Also expected to unfold over winter was a positive Indian Ocean Dipole (IOD), which is currently neutral but models are suggesting a switch to positive in the coming weeks.

A positive IOD typically suppresses winter and spring rainfall over much of the country, and if it occurs with El Niño, it is likely to exacerbate El Niño’s drying effect.

The Pacific Ocean is currently El Niño Southern Oscillation (ENSO) neutral – neither La Niña nor El Niño – but the Bureau of Meteorology said the outlook was at “El Niño WATCH”.

Most parts of Australia will record warmer temperatures than usual over winter. Picture: BOM

The agency said this indicated there was an increased risk of an El Niño occurring this year, at least double the usual chance.

Australia had a drier Autumn than usual and below average rainfall, with it about 70 per cent below typical levels.

“This May has been one of Australia’s driest on record,” the BOM said, adding it had also been the coolest Autumn in almost a decade.

Average overnight temperatures were below average in almost all locations, she said.

Large parts of the country have a high chance of unusually low rainfall throughout winter, with some areas in the south almost three times as likely to have rainfall in the lowest 20 per cent of records.

While most areas will record warmer temperatures than usual over winter, there will still be occasions of chilly blasts.

The winter long-range forecast shows it's likely to be drier and warmer than usual for most of #Aus with an increased chance of unusually high winter daytime temperatures for the south. Models show both El Niño and positive IOD conditions may develop: https://t.co/XDzA9BFYmBpic.twitter.com/YOExcmdTLA

— Bureau of Meteorology, Australia (@BOM_au) June 1, 2023

Australia’s weather is influenced largely by El Niño and La Niña which have a strong influence on year-to-year climate variability.

They are associated with a sustained period of many months of warming – El Niño – or cooling – La Niña – in the central and eastern tropical Pacific.

BOM said the ENSO cycle typically operated over timescales from one to eight years.

Australia has a high chance of unusually low rainfall throughout winter. Picture: BOM

In addition to “abnormal” reduced rainfall and warmer temperatures, El Niño was expected to cause a shift in temperature extremes, an increased frost risk, reduced tropical cyclone numbers, later monsoon onset, increased fire danger in southeast Australia and decreased alpine snow depths.

“While this winter will still have plenty of cold weather, rain, snow and frost, two broadscale climate drivers could team up and make some types of weather more likely than others,” Weatherzone said in its outlook.

“Warm days and cold, frosty nights are typical during El Nino and a positive IOD winter,” Weatherzone said.

“This is because clearer skies allow more heating to occur during the day, while radiative cooling is more prevalent during the clear nights.”

Originally published as Australians to expect unusually warm and dry winter conditions