Rain Pummels East Coast As Ex-Cyclone Triggers Severe Weather Warning

Ex-Tropical Cyclone Esther is moving into NSW's north-east, causing flash flooding and heavy rainfall across the state.

Rain is expected to intensify into Wednesday night and continue on Thursday across a large swathe of NSW.

The Bureau of Meterology has issued a severe weather warning, with flash flooding expected across the Upper Western, Lower Western, Riverina, Lower Central West, Southern Slopes, Snowy Mountains, Southern Tablelands regions and the Australian Capital Territory.

"Ex-Tropical Cyclone Esther, currently near the Northern Territory-Queensland border, is approaching New South Wales and deepening a low pressure trough over the western inland," BOM wrote on its site.

"Widespread rain is expected across the inland and southeast of New South Wales during Wednesday as this trough deepens. Thunderstorms are also possible."

A 500km rain band is set to unleash on capital cities as it moves across Central Australia to the south-east coast.

In light of the drenching, BOM has warned bushfire-affected regions should be wary of dangerous debris.

Sydney is likely to see 15mm of rain on Wednesday and up to 20mm on Thursday.

Melbourne could also experience a soaking of up to 10mm tomorrow, according to BOM.

Pedestrians hold umbrellas as they walk in heavy rain in Sydney's CBD, Friday, January 17, 2020. Image: AAP

"A major rain event is on our hands. On Wednesday and Thursday, a 500km-wide band of rain will stretch from Alice Springs all the way to Melbourne and Sydney," Sky News Weather meteorologist Rob Sharpe said.

"Our modelling shows the most consistent and widespread rainfall will be straight through the middle of the Murray-Darling Basin."

It would be the best rain the basin has seen since December 2017.

With AAP