Wet weather is set to drench Australia's eastern coast while the nation's west prepares for a record-breaking heatwave, but in lucky news for millions out east - La Nina is nearly over.
Heavy rain is expected in both parts of NSW and Queensland on Thursday due to the remnants of ex-tropical cyclone Tiffany and a secondary coastal trough.
After weeks of wild weather and even more unpredictable surf, La Nina is now expected to peak in the next few weeks and fizzle out by March.
Meanwhile, other parts of the country will sizzle through consecutive 40C days as heatwaves strike Western Australia and Victoria.
Weatherzone meteorologist Joel Pippard said: 'What's left over from cyclone Tiffany is crossing northern NSW and will spread into Queensland tomorrow.
The remnants of ex-cyclone Tiffany will bring a mega rain bomb to Australia's east coast affecting parts of NSW, QLD and SA (pictured, Sydneysiders shelter from the rain)
The Bureau of Meteorology warned storms could bring flash flooding around northern ranges, far northern slopes and the northern inland in NSW
'It has quite a bit of tropical moisture in it so we're seeing fairly widespread rain across going on across the region with some thunderstorms in the north.'
Mr Pippard added a secondary system was developing over the same region with heavy rainfall forecast for parts of NSW over the next two days.
'A coastal trough is developing off the northern NSW coast, that one is going to stick around for the next two days and bring heavy rainfall for that region,' he said.
'By the end of tomorrow there could be some areas that pick up 80 to 120mm of rain - that's most likely between the mid north coast and the northern rivers district.'
The Bureau of Meteorology warned storms could bring flash flooding around NSW's northern ranges, far northern slopes and the northern inland.
The Bureau of Meteorology has issued a severe heatwave warning for Perth and WA's south west from Tuesday until Thursday
A record-breaking heatwave is set to hit Perth (pictured) with residents expected to cop the heat all the way through to Thursday
Damaging winds are also a possibility for storms in Bourke and Tibooburra and other north western regions.
A severe weather warning for damaging winds has also been issued for the South West Slopes, the Hunter, Central Tablelands, Southern Tablelands, North West Slopes and the Snowy Mountains.
Rainfall is expected to ease across the north-east by Friday as the system moves towards the far west bringing the possibility of thunderstorms over the weekend.
Sydney will miss out on the brunt of the deluge with showers expected in the morning and late afternoon on Saturday and Sunday.
'There's a little bit of wet activity but none of it is looking that heavy, so there'll be times to get outside during the weekend,' Mr Pippard said.
Five states are set to be soaked this week as ex-tropical cyclone Tiffany barrels a low pressure system across parts of the NT, SA, NSW, VIC, and QLD. Pictured: Sydneysiders braving the rain
Slow moving thunderstorms with damaging winds and heavy rainfall have continued to develop in parts of QLD on Wednesday.
The Bureau issued a severe thunderstorm warning for Thargomindah, Roma, Charleville, St George, Quilpie and Windorah.
Lifeguards have also closed six beaches in the Cairns Region due to hazardous surf conditions.
South Australia will bear the brunt of the multi-state wild weather event, with parts of the state expected to see up to 150mm of rain and potential flooding.
While the wet conditions have hit Queensland and NSW earlier, the western side of the system - which is currently sweeping across outback NT and SA - will reach Adelaide on Friday.
Once it
