Australia is bracing for a dramatic weather split this week as a rare atmospheric phenomenon triggers scorching heat in the north and destructive storms across the south.
A clash of wind and air currents 30 km (19 mi) above Antarctica has suddenly thrown Australia’s spring and summer forecast into question. Last week, a dramatic event known as a Sudden Stratospheric Warming (SSW) sent stratospheric temperatures soaring by more than 30°C (54°F) in just seven days.
SSW is rare in the Southern Hemisphere, but when it does occur it can significantly alter weather patterns at the surface. Waves of air surged upward, clashed with strong Antarctic winds and lost energy, creating a large pool of unusually warm air near the ozone layer.
Dr Martin Jucker, a lecturer at the Climate Change Research Centre at the University of New South Wales, explained that while the exact mechanisms remain unclear, the effects on Australia are well documented. “We know that if this bunch of air at 30 kilometres warms, we know that after that, surface weather patterns behave differently,” he said. “It causes often warmer and drier than usual conditions in south-eastern Australia. It didn’t cause the bushfires in 2019, but it made them worse because it just made conditions even worse — even more fire-prone.”
Here's an overview of what we can expect from the weather for tomorrow, Tuesday September 30.
— Bureau of Meteorology, Australia (@BOM_au) September 29, 2025
It will be sunny and warm across central and northern parts of #Aus. Rain and strong winds will affect parts of the south.
Latest: https://t.co/4W35o8i7wJ pic.twitter.com/611UCxxNcd
The Bureau of Meteorology confirmed signs of the SSW are already influencing Australia’s weather. Meteorologist Andrew Hines said on Monday that a powerful cold front is moving across South Australia, Victoria and Tasmania, bringing damaging winds and heavy rainfall. “A cold front is about to cross southern parts of Australia – including South Australia, Victoria and Tasmania – bringing a risk of damaging winds and heavy rainfall to some parts over the next few days,” he noted.
Rainfall will be concentrated in South Australia and Tasmania. The Limestone Coast in the southeast and much of western Tasmania could see up to 80 mm (3.1 in) of rain, while Victoria’s northern Gippsland is forecast to receive severe wind gusts of up to 100 km/h (62 mph) on Tuesday. Flood watch warnings are in effect for much of Tasmania, where already saturated catchments heighten the risk of riverine flooding.
Cooler, wetter conditions are also expected in Melbourne and Adelaide, with showers on multiple days and maximum temperatures unlikely to exceed 20°C (68°F).
In stark contrast, northern and eastern Australia are heating up. Maximum temperatures on Thursday are forecast to hit 28°C (82°F) in Sydney, 35°C (95°F) in Brisbane and 40°C (104°F) in the Kimberley region. The Northern Territory, Queensland and New South Wales are all facing spells of unseasonably high temperatures, with Weatherzone warning that the combination of heat and dry conditions will increase bushfire risk. High fire danger is likely across broad areas of Western Australia, the Northern Territory, Queensland and New South Wales.
Senior climatologist Zhi-Weng Chua of the Bureau of Meteorology said the SSW is likely contributing to the unusually hot weather in the east and north. “It’s hard to really attribute [the hot weather] to one factor but it’s likely that the SSW is playing into some of these temperatures,” he explained.
The Bureau issues warnings when severe and extreme heatwaves are forecast.
— Bureau of Meteorology, Australia (@BOM_au) September 29, 2025
Heatwaves can be dangerous for everyone, so it's important to understand heatwave warnings to stay safe. Learn more: https://t.co/gWVr5mQRw4 pic.twitter.com/ysphXTADzq
Looking ahead, the long-range implications of this SSW remain uncertain. While SSWs often push Australia toward hotter, drier conditions, ocean patterns are currently pulling in the opposite direction. The Bureau has highlighted the influence of a negative Indian Ocean Dipole, which tends to bring above-average rainfall to much of eastern Australia.
