Heavy rain, thunderstorms and flash flooding could hit large swaths of Australia this weekend, with more rain expected after a week of wet weather.
A high pressure system centered just south of the country is absorbing moisture from the atmosphere that will turn into rain as it encounters a pool of cold air at upper levels over the next few days.
New South Wales and Victoria will be affected, while southern Western Australia, eastern South Africa and southern Queensland will also experience significant drops.
The northern half of the country will receive some rain but will remain mostly dry, while Tasmania will see cool, cloudy conditions but avoid significant rainfall.
Rain in the eastern half of the country will move from South Africa towards the coast, reaching Melbourne on Friday and Sydney late Friday night.
Southeastern Australia will be drenched over the weekend, as this map of accumulated rainfall for the seven days to Tuesday shows.
Sydneysiders should carry an umbrella if they venture out this weekend and those further south in the Illawarra and South Coast should keep an eye out for flood warnings.
Already saturated catchments in New South Wales and Victoria could rapidly flood, particularly in the Illawarra and south coast regions of New South Wales, where weekend rainfall totals could exceed 150mm.
The Bureau of Meteorology’s Sarah Scully said the upper-level trough will combine with a coastal trough over New South Wales on Saturday and “increase” rainfall.
“Moderate to heavy rainfall is expected across the southern half of New South Wales,” Ms Scully said.
‘We expect to issue a severe weather warning as grounds are very wet in eastern parts of New South Wales due to recent rain.
“In inland NSW, rainfall totals look to exceed 50mm over the weekend, even reaching 100mm in some places.”
The Bureau also has a dangerous surf warning for Saturday for the Macquarie Coast, Hunter Coast, Sydney Coast and Illawarra Coast.
Canberra, Brisbane and Cairns will see some showers over the weekend and mild temperatures, with Canberra falling into single figures overnight.
Darwin and Adelaide will have a good weekend with highs in Adelaide in the 20s and Darwin in the 30s.
Rainfall will ease on Tuesday in most parts of the country.
The second half of next week is forecast to be pleasant, albeit with cool autumn weather.
Rain will be concentrated in the eastern and southwestern parts of the country with the central and northern regions escaping most of the rain.
Sea surface temperatures remain the warmest on record globally since April 2023, which is impacting historical modeling to declare climate events such as El Niño or La Niña.
The bureau said sea surface temperatures continue to rise, with temperatures in February, March and April setting records.
The Pacific Ocean is likely to return to a neutral pattern (known as the El Niño Southern Oscillation or ENSO), neither El Niño nor La Niña, by June.
There are also predictions that La Niña will return in late winter, but the forecasts will not be firm enough to declare this until after May.
“El Niño and La Niña predictions made in early fall tend to be less accurate than predictions made at other times of the year,” the office said.
“As current global ocean conditions have not been observed before, inferences about how ENSO will develop in 2024 based on past events may not be reliable.”
La Niña conditions generally result in higher precipitation totals and cooler average daytime temperatures.