Severe weather conditions are being experienced across the country with heatwaves in parts of Western Australia, Victoria and NSW, while Queenslanders are being warned about thunderstorms and the risk of river levels rising.
Balmy conditions are expected to persist in eastern Victoria, northeast Tasmania, the ACT, southern NSW and inland parts of South Australia and Western Australia.
These places should brace for another day of daytime temperatures 6C to 8C warmer than usual seasonal averages, the Bureau of Meteorology (BoM) said.
Second death confirmed in flood-hit Queensland
In Queensland, where hundreds of people have been forced to leave their homes after intense flooding hit parts of the state, conditions are expected to ease from Tuesday, but forecasters are warning there's still a risk of localised heavy rainfall that could lead to flash flooding in the Townsville region.
The death toll in the state has risen to two after the body of an 82-year-old woman was found in a cane field at Bemerside, near Ingham on Tuesday morning.
A neighbour raised concerns for her welfare after she was unable to find the woman at the property on Tuesday morning.
"The woman was located deceased a short time later by the resident after floodwaters receded," police said.
The Ingham community is already reeling after a 63-year-old woman died when an SES boat helping people through floodwaters struck a tree and flipped on Sunday.
The BoM warned that Tuesday could bring local heavy rainfall between Cairns and Townsville with a severe weather warning in place between Cardwell and Yabulu.
"Rainfall totals are expected to be lower than they were during the past weekend, but the rain is likely to be enough to prolong the existing flooding and potentially cause new areas of flooding," the BoM's Miriam Bradbury said.
She added there were still major flood warnings for a number of catchments including the Herbert, Burdekin and Horton Rivers.
"Some catchments are holding steady or even starting to fall, but others are still continuing to rise in response to past rainfall," Bradbury told the Australian Associated Press.
Less than 10,000 homes across the north were without power on Tuesday, with nearly three-quarters of those in Ingham.
Food, fresh water and diesel are believed to be running low, with Queensland Premier David Crisafulli set to visit via helicopter.
Heatwaves for regional NSW
There are severe heatwave warnings for the South Coast and Snowy Mountains Districts, which are expected to gradually ease later in the week.
Low-intensity heatwave conditions will persist over much of the state until the weekend — except in the far northeast, according to the BoM.
Sharp cool change for Victoria
A cool change hit Victoria on Tuesday afternoon, but the bushfire danger remains high as thunderstorms sweep through the state's west.
The mercury plummeted 12C in just one hour in Melbourne while cooler weather and gusty winds set in across fire-hit areas.
A thunderstorm caused a fresh round of lightning strikes at the southern end of the Grampians national park in the state's west, with fears of more to come.
Wild winds have wreaked havoc on three out-of-control bushfires at Little Desert National Park near the South Australian border, Wallaby Rocks the in northern Grampians National Park and Victoria Range in the park's south.
At the same time, heatwave warnings remain across much of Australia.
— With additional reporting by the Australian Associated Press.
