Millions of Aussies told to brace for heavy downpours and flash flooding as mammoth weather system moves across the country

Published: 05:06, 24 August 2026 | Updated: 05:10, 24 August 2026 Australians have been warned to brace for heavy downpours and flash flooding, with millions in the firing line of a low pressure system moving across the country.  Northeastern Victoria and southern NSW are expected to bear the brunt as the weather system tracks from the west to the east coast.  'It'll bring quite heavy rain to many areas, particularly northeastern Victoria and … as far as southern NSW, into the hills there,' Bureau of Meteorology senior meteorologist David Crock told NewsWire. 'Some of those areas could see sort of 40 to 60 millimetres of rain on Tuesday, again with some higher totals possible there and those catchments, particularly (in) northern Victoria, (are) really wet at the moment.'  Flood warnings for the Kiewa, Loddon and Avoca catchments have been issued, with river levels expected to rise between Monday and Wednesday.  Affected rivers include the Upper Murray and Mitta Mitta, Kiewa, Ovens, King, Broken, Seven and Castle Creeks, Goulburn River Eildon to Seymour and downstream, Loddon and Avoca.  '(We're) likely to see more flooding in some of those northern Victorian catchments from… Tuesday onwards,' Mr Crock said. The weather system began over far eastern Western Australia and southern Northern Territory before reaching South Australia on Monday.  Australians have been warned to brace for heavy downpours and flash flooding, with millions in the firing line of a low pressure system moving across the country Northeastern Victoria and southern NSW are expected to bear the brunt as the weather system tracks from the west to the east coast 'The low really kicks off with rain and storms across much of South Australia, parts of the Eyre and Yorke peninsulas and the Adelaide Hills could see locally heavy rain of 30 to 50 millimetres,' Mr Crock said.  'That low could see some rainfall totals of … 20 to 40 millimetres, and perhaps a few higher totals accumulate over the course for the second half of (Monday) and into Tuesday morning.' He said those areas were already drenched prior to the system arriving.  'Many of those areas are quite wet already following a couple of good rain events in recent weeks, particularly in the Adelaide Hills about ten days ago or so,' Mr Crock said. 'Even if the rain numbers aren't that high, there could be some substantial impacts in terms of creeks running and flash flooding.' According to the Bureau, the Far West Coast, Upper West Coast, Lower West Coast, Central Coast and Spencer Gulf could also see strong winds.  From there, the weather system will continue tracking east before reaching the Tasman Sea on Wednesday. Before it disappears, Mr Crock said eastern NSW and southern Queensland would receive some welcome rain. Flash flooding and storms are expected across Australia this week, with northeastern Victoria and southern New South Wales forecast to bear the brunt of the low-pressure system  'Those areas are much drier this winter so far, so they'll be happy to see more rain,' Mr Crock said. '(A) big system, bit of thunderstorms and flooding, but then also good news for some who need more winter rain.' Monday: Max 18. Partly cloudy. High chance of showers, most likely at night. Winds northerly 15 to 25 km/h becoming light in the evening. Tuesday: Min 11. Max 16. Cloudy. Very high chance of rain, most likely in the morning. Light winds becoming south to southwesterly 15 to 20 km/h in the early afternoon. Wednesday: Min 9. Max 15. Partly cloudy. Slight chance of a shower, most likely in the morning. Winds west to southwesterly 15 to 20 km/h turning southerly during the afternoon. Monday: Max 20. Sunny. Winds northeasterly 15 to 25 km/h tending northerly 15 to 20 km/h in the late evening. Flood warnings for the Kiewa, Loddon and Avoca catchments have been issued, with river levels expected to rise between Monday and Wednesday Tuesday: Min 14. Max 22. Cloudy. Very high chance of rain, most likely from the late morning. Light winds becoming northerly 15 to 25 km/h in the morning then becoming light in the evening. Wednesday: Min 14. Max 20. Partly cloudy. High chance of showers, most likely in the morning. The chance of a thunderstorm in the morning. Light winds becoming southwesterly 15 to 25 km/h during the morning then tending southerly 20 to 30 km/h during the day. Monday: Max 24. Partly cloudy. Medium chance of showers, becoming less likely in the late afternoon and evening. Light winds becoming easterly 15 to 20 km/h in the late afternoon then becoming light in the evening. Tuesday: Min 15. Max 26. Partly cloudy. Slight chance of a shower. Light winds becoming northeasterly 15 to 20 km/h in the early afternoon then becoming light in the evening. Wednesday: Min 16. Max 27. Partly cloudy. Very high chance of showers, most likely in the morning. The chance of a thunderstorm in the morning. Light winds.  Monday: Max 16. Cloudy. Very high chance of rain. Winds northeasterly 15 to 25 km/h becoming light in the late evening. According to the Bureau, the Far West Coast, Upper West Coast, Lower West Coast, the Central Coast and Spencer Gulf could expect strong winds as well Tuesday: Min 12. Max 17. Partly cloudy. Very high chance of rain, most likely in the morning and afternoon. Winds southwesterly 20 to 30 km/h tending southerly 15 to 20 km/h in the evening then becoming light in the late evening. Wednesday: Min 7. Max 17. Partly cloudy. Light winds.  Monday: Max 19. Partly cloudy. Light winds. Tuesday: Min 8. Max 22. Partly cloudy. Slight chance of a shower. Light winds becoming north to northwesterly 15 to 25 km/h in the morning then becoming light in the evening. Wednesday: Min 9. Max 21. Cloudy. Very high chance of showers, most likely in the afternoon and evening. The chance of a thunderstorm in the morning and afternoon. Winds northwest to northeasterly 15 to 25 km/h tending northwest to southwesterly 20 to 30 km/h during the day then tending south to southwesterly 15 to 20 km/h during the evening. Monday: Max 19. Mostly sunny. Winds northwesterly 15 to 25 km/h becoming light in the evening. Tuesday: Min 6. Max 16. Cloudy. Very high chance of rain, most likely in the morning and afternoon. Light winds becoming northerly 15 to 20 km/h in the early morning then tending northwesterly 20 to 30 km/h in the morning. Wednesday: Min 7. Max 18. Partly cloudy. Medium chance of showers, most likely in the evening. Light winds. Monday: Max 17. Partly cloudy. Slight chance of a shower at night. Winds northwesterly 15 to 20 km/h becoming light in the late afternoon. Tuesday: Min 9. Max 15. Cloudy. Very high chance of showers, most likely in the afternoon and evening. Light winds. Wednesday: Min 8. Max 14. Cloudy. Medium chance of showers, most likely in the morning and afternoon. Winds west to southwesterly 15 to 20 km/h tending south to southwesterly 20 to 30 km/h during the morning then becoming light during the evening. Monday: Max 32. Mostly sunny. Light winds becoming north to northwesterly 20 to 30 km/h in the middle of the day then tending northwest to southwesterly 15 to 25 km/h in the late afternoon. Tuesday: Min 22. Max 32. Mostly sunny. Slight chance of a shower. Light winds becoming north to northwesterly 15 to 25 km/h in the middle of the day then becoming light in the evening. Wednesday: Min 22. Max 34. Sunny. Light winds becoming easterly 15 to 20 km/h during the morning then turning north to northeasterly 20 to 30 km/h during the day.