Severe storms threaten eastern Australia as Queensland faces further flooding

Large areas of eastern Australia faced the threat of severe thunderstorms on Sunday, October 25, as a weather system crossing several states brought warnings of hail, damaging winds and flash flooding. The Bureau of Meteorology said storms could also cause power outages, with further storm activity and flood risks expected on Monday.

The area at risk on Sunday afternoon stretched across southern Queensland, western New South Wales, the Australian Capital Territory and eastern Victoria. A broad band of storms had already passed through western NSW, and wind gusts reached 100km/h in the state's central west around midday. The bureau warned that additional thunderstorm warnings were likely during the evening.

Bureau meteorologist David Crock described the system as “unusually large”. He said high pressure over the Tasman Sea had blocked weather fronts for the previous 10 days, contributing to storms and rain in southern Queensland. A sufficiently strong weather system was now displacing that pattern, a process he said typically produces severe conditions.

A cooler air front advancing from the west on Sunday afternoon was drawing tropical moisture southward, creating storm conditions across central NSW and Canberra. Crock said a line of storms stretched from the Snowy mountains to the Queensland border. Forecasters were also monitoring the possibility of a second band forming behind it.

As the cold front continued moving through, storms were expected to persist through Sunday evening and into Monday across northern NSW and southern Queensland. Crock said Monday was expected to bring the system's final major burst of activity, offering the prospect of relief for communities in south-east Queensland after days of torrential rain.

Eight flood warnings were in effect across southern Queensland. At Tiaro, downstream of Gympie, the Mary River was forecast to reach major flood levels on Sunday evening and into Monday. Crock described the past week's conditions in southern Queensland as weather “whiplash”: a very dry September had been followed by October rainfall several times the monthly average. Areas around the Sunshine Coast received between 200mm and 400mm over the previous week.

The bureau's long-range outlook for November through January indicates that rainfall is likely to exceed average levels across most of Australia. The far north and much of Tasmania are exceptions to that forecast.

November temperatures are also likely to be higher than usual across the southern half of the continent. Overnight temperatures are forecast to be particularly elevated, with much of the country likely to experience nights well above average. The bureau's long-term climate records show that global heating has increased Australia's temperature by about 1.5C since 1910.