Much of coastal NSW from the south of Sydney to the Victorian border will face the wrath of a complex low-pressure system that will bring heavy rain, hazardous surf and even flash flooding in places.
The Bureau of Meteorology has issued several warnings for severe weather, with a trough expected to deepen, generating “multiple low-pressure centres” late on Saturday and into Sunday. The latest alert covers a coastal strip from near Kempsey all the way south to Moruya Heads.
For Sydney, the rain should arrive by late Sunday morning, with the chance of a thunderstorm. Falls may be heavy by the late afternoon or early evening, the Bureau said. The city may collect 35-50 millimetres of rain on Sunday.
Several places had already clocked up more than 150 millimetres of rain in the 24 hours to 9am on Saturday, including 154 millimetres at Nowra. That town collected another 38 millimetres by late on Saturday and the bureau had received another 110 millimetres by Sunday morning.
“Heavy rainfall, which may lead to flash flooding and riverine flooding, is forecast for the South Coast and Illawarra districts, and eastern parts of the Snowy Mountains and Southern Tablelands districts today and Sunday,” the bureau said.
Minor to moderate flooding is already underway in some southern catchments, such as the Moruya River and the Shoalhaven River.
Large and powerful surf conditions are expected to be hazardous for coastal activities such as rock fishing, swimming and surfing.
Still, the coast from the Illawarra to the Central Coast, including Sydney’s eastern edge, may be buffeted by damaging winds gusting in excess of 90km/h during Sunday.
Locations which may be affected include Sydney, Wollongong, Nowra, Bowral, Batemans Bay, Eden, Braidwood, Bega, Moruya Heads and Bombala, the bureau said.
A separate bureau warning for hazardous surf includes the Sydney and Illawarra coasts, and further south to Batemans Bay and Eden.
Ben Domensino, a senior meteorologist at Weatherzone, said offshore wave heights could exceed five metres off Sydney as the swell builds on Monday.
Two east coast lows pummelled eastern NSW in July and there is the prospect of another low pressure system forming in the Tasman Sea late next week.
In the meantime, showers will start to clear for Sydney by Tuesday, with Thursday likely to be the pick of the days before the rain returns for next weekend.
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Peter Hannam writes on environment issues for The Sydney Morning Herald and The Age.