A humid air mass has created a serious storm risk in many parts of the country, exacerbating flood risk in already saturated East Coast watersheds.
Steve Bernasconi, manager of the Bureau of Meteorology, for hazard preparedness and response, says severe thunderstorms and widespread rain are expected for Sunday.
“All of this adds to the existing long-term flooding that is happening in inland NSW,” he said.
Heavy slumps are forecast for Sunday for parts of NSW and Victoria, as a moist, humid air mass moves to the northeast, bringing isolated storm cells to parts of Queensland and the Northern Territory.
Conditions are expected to ease around Tuesday with cooler, drier and calmer conditions.
The NSW SES has established a flood rescue center in Goulburn and is positioning personnel and vehicles in areas of concern including Albury, Young, Yass, Wagga Wagga and other towns along the Murray River system.
A severe thunderstorm warning has been issued in central NSW, covering the regions of South West Slopes, Central West Slopes, Central and Southern Tablelands, Riverina and Snowy Mountains, with severe falls that could lead to life-threatening flash flooding predicted for Sunday evening.
The SES has put in place 75 warnings, including five emergency warnings to evacuate.
Commissioner Carlene York urged people to follow the SES warnings and evacuation orders.
“Some people still don’t listen, but unfortunately they make their decisions based on what they have seen in the past,” said Ms York.
“But we’ve seen time and time again that the water rises further than it may have been for many years and that’s because of the saturation of the land.”
The volunteer workforce is tired and personnel from other states have been requested, she says.
Steph Cooke, NSW’s emergency services minister, says communities across the state are also fatigued, including in Gunnedah, which she visited on Saturday.
“That community has experienced eight floods in the last 12 months and it’s taking a toll on the people,” she said.
“There is no panacea for what we are experiencing right now and will likely continue to experience it for a while.”
The SES will continue to supply food and medicine to flooded communities, covering an area of more than 40,000 square kilometers, roughly the size of Switzerland, Ms Cooke said.
Ms York says some communities will be isolated for weeks, if not months.
In northeastern Victoria, heavy showers, triggered by storms, are expected to cause flash flooding, with falls of up to 150mm in 24 hours in alpine areas.
A severe weather warning was issued Sunday afternoon for possible flash flooding in East Gippsland, South Gippsland, Northern Country, North Central and Central West.
Areas of special interest include Seymour, Wodonga, Wangaratta, Corryong, Bright, Mansfield, Falls Creek, Mt Hotham, and Mt Buller.
Major and moderate flooding is occurring in northern Victoria and the rains, combined with an already saturated catchment and dam leaks, are expected to lead to further and rapid rises in parts of the Murray and Edward Rivers.
In the Northern Territory, severe storms develop in Carpentaria and parts of Arnhem and Barkly districts on Sunday afternoon as a moist air mass moves past a surface trough.
Severe falls with possible flash flooding are forecast in Borroloola, Mataranka, Ngukurr, Larrimah, Beswick and Wollogorang.
In Queensland, severe storms are forecast for Sunday, and are expected over Mount Isa, Cloncurry, Dajarra, Duchess, Selwyn and Mckinlay in the far north of the state.
The intense storms that hit the eastern states swept through South Australia on Saturday, with more than 423,000 lightning strikes and severe winds cutting down trees and damaging electricity infrastructure.
SA Power Networks estimated on Sunday that 100,000 customers had had their supplies hit and has engaged highway power crews to help with ongoing restoration work.