Victoria and Tasmania are forecast to receive the brunt of the torrential rain this time around but the flooding continues in New South Wales.
This week it's a slow-moving cold front and surface trough that's dragging moisture down from the La Niña and negative IOD-charged tropics.
"It's a double source of moisture converging over the south-east, which is driving this tropically sourced heavy rainfall," said Bureau of Meteorology forecaster Jonathan How.
The rain is expected to start today, with the main peak tomorrow before things clear off again by the weekend.
As always, please keep up with the warnings at ABC Emergency and refer to its information on what you should do to get ready if the worst happens.
Here's what to expect near you.
South Australia
South Australia is where things are kicking off this morning.
The rain will start in the north and sweep south-east as the day goes on.
"By the afternoon, we will see a band of rain extend all the way from the Western Australian border, through into the northern parts of Eyre Peninsula, mainly remaining north of Adelaide and down towards the south-east," Mr How said.
Today the rain will be in the north-west but tomorrow will be the peak of the rain in the south-east.
It looks like Adelaide will remain just on the edge of the rain band missing out on the biggest totals but, in the Riverland, falls are expected to be 40 millimetres or more, according to Mr How.
"Of note on Thursday is how cold it will be across SA. Behind the cold front we have a mass of very cold moving up," he said.
Maximum temperatures are expected to be 8 degrees Celcius to 16C below average on Wednesday and Thursday.
Oodnadatta is only expected to get up to a maximum of 17C on Thursday after a top of 33C on Monday.
Victoria
Showers are expected to develop today but the peak will be tomorrow.
"Pretty much from the get-go on Thursday we'll see some heavy falls developing first about the Mallee, the Wimmera and the northern country and then gradually seeping its way down into the Melbourne area," Mr How said.
Melbourne is usually in a rain shadow when the rain comes from the north, but the shadow will delay rather than completely prevent the rain this time around, according to Mr How.
Rainfall totals for Thursday in Victoria are expected to be broadly 20–60mm.
"But the focus of rain will be across the ranges from the Grampians, through the Central Highlands [and] up into the north-east," he said.
"Falls potentially up to 80–100mm, including [in] places like Bendigo, Seymour, Castlemaine, and up towards the north-east as well."
Melbourne should expect 30–50mm but with possible heavier falls, particularly in the afternoon and evening, according to Mr How.
"Flash flooding will be a significant risk for Victoria, including Melbourne," he said.
Renewed moderate and major flooding is likely for the north and centre of the state as the rain persists into Thursday evening.
By Friday the rain should push into the east of the state, bringing the rain to Gippsland but the flood threat will remain.
"The messaging for everyone is: Be careful with flash flooding and landslips will be a real concern across Victoria," Mr How said.
"We have already seen some landslips with the recent rain about [are] expecting more to come."
If that isn't enough, Mr How warns a low is expected to form.
"Because of the cloud cover, most of those strong winds won't be able to make it down to the surface," he said.
"But we are expecting [the] possibility of damaging winds for the central ranges and the north-east alpine areas on Thursday as well.
"So heavy, lashing rainfall for elevated areas."
Tasmania
Tasmania will see the highest falls in the country from this rainfall system.
Like in Victoria, the rain is expected to start today and ramp up to its peak tomorrow.
"[We're] looking at widespread falls through northern Tasmania [of] 50–100mm and isolated falls possibly getting up to 150mm," Mr How said.
"And even more isolated falls of 200mm are possible through parts of the elevated areas."
"This kind of moist northerly air regime is a classic set-up for heavy rainfall due to orographic lifting across the northern parts of Tasmania," he said.
Flooding is currently looking like it will be mostly moderate but isolated major flooding is also a risk.
The Strait is not going to do anything to stop the wind that's expected to thrash Victoria, so, Taswegians must be ready for that too.
Hobart is at least protected from this northern rain by the mountains but the forecast is still for 20–30mm.
New South Wales and ACT
The heaviest falls for New South Wales are expected through the south of the state, in particular, "the Riverina and towards the Broken Hill area", according to Mr How.
"The one good news out of this is that most of the rain will fall to the west and the south of where we're seeing the major flooding," he said.
But even though it might be less than elsewhere, the rain that does fall will still likely lead to new flood peaks, so keep up with the flood watches and warnings.
The rain is expected to push through NSW Thursday and into Friday, getting to the coast and Sydney Friday morning.
But with a bit of luck it will move off pretty quick, with most of the state dry by Friday evening.
Queensland
The south-west of Queensland could get rain late Thursday into Friday.
"But it does weaken quite rapidly as it moves across the south of the state," Mr How said.
"By the time it gets to south-east Queensland, it will mostly have dried out."
Showers for the Downs and a few millimetres are on the forecast for Brisbane and the Gold Coast.
More showers are possible further north, but nothing out of the ordinary.
Enjoy not being the focus of these weather wraps while it lasts, Queensland.
Northern Territory
It's the build up.
"We are looking at the possibility of storms across the Top End pretty much every day this week," Mr How said.
Away from the storms, high humidity and temperatures are resulting in heatwave conditions.
But in the south of the state it is a very different story.
If you are camping out at Uluru I hope you packed a decent sleeping bag because all that cold air pushing up through SA is going to make it up to you.
After reaching 35C yesterday and 31C today the maximum is forecast to drop to just 16C on Thursday, with a high chance of showers before getting all the way down to 4C overnight into Friday.
Alice will drop from a maximum of 39C today to a high of just 24C on Thursday.
Western Australia
Being last sucks, but not getting a leading role in the weather wrap is generally a good thing.
Way over near the border, there could be a few showers, but the rest of WA is missing out.
You can commiserate with the other southern states about the cold though.
"Maximum temperatures over the next few days all the way up into the Pilbara are looking 5C to 15C below average," Mr How said.
"Including for Perth, it's in the low 20s, which is slightly below average [for] this time of year but [expect] mostly dry conditions."
But it won't last for long. A high sliding on over on the weekend should warm things up.
Finally, for anyone up at the Ashburton Coast and the Exmouth Gulf Coast, please also keep your wits about you as the fire danger rating for today is expected to be extreme.
