Heavy rain, thunderstorms and flash flooding could hit large parts 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 pulling moisture from the atmosphere, which will turn to rain in the coming days as it encounters a pool of cold air at higher levels.
NSW and Victoria are set for a dip, while southern WA, eastern SA and southern Queensland will also see significant declines.
The northern half of the country will see some showers but remain largely dry, while Tasmania will see cool and cloudy conditions but avoid significant rainfall.
Rain in the eastern half of the country is moving from South Africa to the coast, hitting Melbourne and Sydney late Friday evening.
Southeast Australia will see rain this weekend, as shown in this cumulative rainfall map for the seven days to Tuesday
Sydneysiders should take an umbrella if they head out this weekend and those further south in the Illawarra and the South Coast should keep an eye out for flood warnings
Already saturated catchments in NSW and Victoria could flood quickly, especially in the Illawarra and south coast regions of NSW, where rainfall could total more than 150mm over the weekend.
Sarah Scully from the Bureau of Meteorology said the upper level trough will combine with a coastal trough over NSW on Saturday and rainfall will increase.
“Moderate to heavy rainfall is expected across the southern half of NSW,” Ms Scully said.
‘We expect to issue a severe weather warning as grounds in eastern parts of NSW are very wet as a result of recent rainfall.
‘In inland NSW, rainfall totals look set to exceed 50mm this weekend, with up to 100mm in some places.’
The Bureau has also issued a hazardous surf warning for the Macquarie, Hunter Coast, Sydney Coast and Illawarra Coast for Saturday.
Canberra, Brisbane and Cairns will see some showers and mild temperatures this weekend, with Canberra dipping into the single digits overnight.
Darwin and Adelaide are in for a nice weekend with highs in Adelaide in the low 20s and Darwin in the low 30s.
From Tuesday, rain will decrease in most of the country.
The second half of next week is expected to be fine, albeit cool, fall weather.
The rain will be concentrated on the eastern and southwestern parts of the country, while the central and northern regions will escape most of the rain.
Sea surface temperatures remain the warmest globally since April 2023, impacting historical models for explaining weather events such as El Nino or La Nina.
The agency said sea surface temperatures continue to rise, with temperatures in February, March and April setting records.
The Pacific Ocean will likely return to a neutral model (known as an El Nino Southern Oscillation or ENSO) in June – neither El Nino nor La Nina.
There are also predictions that a La Nina will return by the end of winter, but the predictions will not be strong enough to make any statements until after May.
“Forecasts of El Nino and La Nina made in early fall tend to have lower accuracy than forecasts made at other times of the year,” the agency said.
‘Since current global ocean conditions have not been observed before, inferences about how ENSO might evolve in 2024 that are based on past events may not be reliable.’
La Nina conditions typically bring higher precipitation totals and cooler average daily temperatures.
