Millions of residents are being warned to brace for a wet and wild weekend, with up to 50mm of rain set to soak Sydney.
The Bureau of Meteorology forecasts an up to 95 per cent chance of showers building across the Harbour City from Thursday.
Falls of up 25mm are expected to douse the city on Friday before building over the weekend to 20-50mm on Sunday.
The autumn downpour is forecast to continue into next week, with as much as 20mm and winds of up 25km/h forecast for Monday and Tuesday.
To the north, residents of the Sunshine State are being told to expect a much milder weekend, with a high chance of up to 6mm of rain on Saturday.
The Bureau of Meteorology forecast a high chance of showers in Brisbane on Saturday, building in the afternoon and evening and continuing into next week.
Saved from the predicted soaking, Melbourne is forecast to be partly cloudy and foggy throughout the week and into the weekend, with zero per cent chance of rain.
The nation’s capital, Canberra, is also forecast to be cloudy, reaching just 18C on Sunday, while Adelaide is expected to be sunny with a maximum temperature of 22C.
While storms were forecast for Perth on Thursday, conditions are expected to ease and the mercury fall into the weekend, with a zero per cent chance of rain on Saturday.
Elsewhere, Darwin is forecast to remain dry over the weekend with a maximum temperature of 35C, while Hobart is set to reach just 17C amid cloudy and overcast conditions.