Heavy rain, wild winds and damaging hail stones have lashed Australia's east coast overnight, with severe thunderstorms storms set to continue throughout the week.
Queensland, News South Wales and Victoria were all blasted with 70km/h gusts causing flash flooding, upturned trees, and leaving thousands of homes without power.
Meteorologists say the conditions are a result of La Nina climate cycle which will make the upcoming summer months hotter and wetter than usual.
For the past 24 hours members of SES have been in Tumbarumba, near the NSW-Victoria border (pictured) helping with flood Rescues
Singleton SES members in the NSW Hunter Valley were called out after reports of severe storm damage (picuted, a caravan is destroyed after wind lifted off several roofs in the park)
The weather map shows forecast for Sydney on Monday, with severe winds set to continue
'There are two low pressure troughs at play. Sydney can expect to more rain through this morning until it starts to ease in the afternoon,' Weatherzone forecaster Ben Domensino told Chanel Nine's Today show.
'The low pressure trough in south-east Queensland could cause severe storms today, and again tomorrow. There will be some easing in the middle of the week, but this weekend another trough moves in.'
'This a fingerprint of La Nina - the big climate driver in the Pacific Ocean. As of the rain that fell in the last 24 hours, Sydney has now reached I think annual average for the year. With two months left to go. And they join Melbourne and Canberra which have already reached their annual averages as well.'
The NSW SES received almost 200 calls for help in the past 24 hours and three millimetres of rain had already hit Sydney on Monday morning.
The bad conditions are predicted to slam the east coast for the next seven days with gusts of up to 70 to 80 km/h likely.
Temperatures have dropped to around 15 degrees, down about eight degrees for this time of year, due to a cold front which saw almost 10 centimetres of snowfall in the alps.
A road and park in Tumbarumba is pictued completely underwater after flash flooding
Pictured: A car in Brisbane that was crushed by a falling tree amid damaging winds and heavy rain
'We do have some hazardous conditions at the moment for the beaches with the strong southeasterly winds whipping up a bigger southeasterly swell up to around four, potentially five metres,' BOM spokeswoman Rebecca Kamitakahara told ABC radio.
'The good news is later in the week we will start to see a little more sunshine ... with those temperatures coming back up to what we'd normally expect at this time of year.'
But the rain has brought relief for farmers across the western ranges and areas west and southwest and parts of the central west.
'They're not seeing as quite as high rainfall totals as what we're getting on the coast but they are still seeing some more steady, persistent rain on top of what they saw on the weekend.' Ms Kamitakahara said.
The rain overnight resulted in the closure of several roads in Sydney's north, with Wakehurst Parkway shut in both directions from Oxford Falls to North Narrabeen, due to flooding.
Galston Road is closed in both directions after a rockfall west of a bridge and drivers are being told to divert.
Pictured: A trampoline in south-east Queensland that wrapped around a power pole in strong winds
Hail the size of tennis balls were seen in Brisbane's western and southern suburbs
Tamworth and Nundle, south-west of Grafton in northern NSW, saw about 60mm of rain on Sunday with an evacuation at a campsite due to flash flooding (regional NSW pictured)
A severe thunderstorm and heavy rain warning that could lead to flash flooding, damaging winds and large hailstones has been issued for Lismore, Grafton, Casino and Yamba on the state's north coast.
Gale warnings have been issued for the Hunter coast, Sydney coast and Illawarra coast alongside strong wind warnings for Sydney waters, the Macquarie coast, Batemans coast and Eden coast.
A damaging winds warning has been issued for parts of the southern tablelands, south west slopes, Snowy Mountains and Canberra.
Surf and swell conditions will be hazardous for rock fishing, boating, and swimming with NSW Police warning people to stay out of the water and avoid walking near surf-exposed areas.
About 30,000 homes across Brisbane, Ipswich, Logan and Redland were been left without power on Sunday as the region was hit with 78,000 lightening strikes and hail the size of tennis balls.
Eastern Victoria can expect the cold, windy conditions to continue over the next few days.
Meanwhile, a trough has also developed over Western Australia and the Northern Territory which is also producing scattered thunderstorms in remote regions.
The south-east Queensland region also had 78,000 lightening strikes on Sunday afternoon
The weather radar shows the trough hovering above Australia's east coast
FIVE DAY WEATHER IN YOUR CITY
Monday : Min 15 Max 15. Showers
Tuesday: Min 14. Max 20. Cloudy
Wednesday: Min 13. Max 22. Showers
Thursday: Min 15. Max 22. Cloudy
Friday: Min 16. Max 25. Showers
Monday : Min 9 Max 17. Windy
Tuesday: Min 9. Max 17. Showers
Wednesday: Min 10. Max 18. Showers
Thursday: Min 10. Max 19. Showers
Friday: Min 11. Max 18. Showers
Monday : Min 6 Max 12. Showers
Tuesday: Min 7. Max 16. Showers
Wednesday: Min 7. Max 19. Showers
Thursday: Min 10. Max 19. Showers
Friday: Min 8. Max 22. Showers
Monday : Min 26 Max 32. Showers
Tuesday: Min 25. Max 33. Storms
Wednesday: Min 25. Max 32. Showers
Thursday: Min 25. Max 32. Showers
Friday: Min 25. Max 32. Showers
Monday : Min 19 Max 29. Showers
Tuesday: Min 19. Max 26. Showers
Wednesday: Min 18. Max 29. Showers
Thursday: Min 18. Max 31. Cloudy
Friday: Min 15. Max 31. Sunny
Monday : Min 8. Max 18. Cloudy
Tuesday: Min 11. Max 20. Cloudy
Wednesday: Min 9. Max 20. Sunny
Thursday: Min 10. Max 21. Showers
Friday: Min 10. Max 19. Showers
Monday : Min 17. Max 27. Sunny
Tuesday: Min 15. Max 24. Cloudy
Wednesday: Min 15. Max 25. Cloudy
Thursday: Min 13. Max 32. Sunny
Friday: Min 18. Max 36. Sunny
Monday : Min 6 Max 15. Cloudy
Tuesday: Min 8. Max 15. Showers
Wednesday: Min 10. Max 15. Showers
Thursday: Min 8. Max 17. Showers
Friday: Min 10. Max 16. Showers
Source: Bureau of Meteorology