Significant thunderstorms are predicted to hit southern and eastern Australia with the potential for widespread flooding in parts of Victoria and southern and central NSW.
The system will move over South Australia on Thursday before impacting Victoria, southern New South Wales and to a lesser degree Tasmania on Friday and Saturday.
Bureau of Meteorology Senior Forecaster Scott Williams said South Australia is expected to experience severe thunderstorms late Thursday into Friday with damaging winds, hail and heavy rainfall.
"The impact area is expected to lie between the Nullarbor and the area north of Adelaide where storms may produce rainfall totals of 50 to 100mm," Mr Williams said.
"The Adelaide area could also be impacted by these storms.
"The system will ramp up over Victoria and western NSW on Friday and into Saturday with rainfalls of 100-200mm expected in these areas, particularly those areas closer to the ranges. Peak falls in the northeast of Victoria could top 300mm over the 48 hours to Saturday night.
"Melbourne is likely to see at least 50 to 100mm of rainfall and severe thunderstorms overnight Friday into Saturday. There is a chance that heavy rain could return to the Melbourne area on Sunday, possibly delivering another 50mm or more.
"Southern parts of NSW and the ACT could see falls in excess of 100mm on Friday and Saturday with some places seeing 200mm. The heavy rainfall could reach Canberra but at this stage does not look like it will impact Sydney."
Updated weather information and warnings are available via the Bureau of Meteorology website or the BOM app.
A weather video update explaining the details of this event can be viewed below: