Cars became stranded in floodwaters in South Melbourne.
Cars became stranded in floodwaters in South Melbourne.
Heavy rain and thunderstorms are bringing widespread flooding to New South Wales and parts of Queensland.

The deluge hit Sydney on Saturday afternoon, as residents were told to brace for conditions to intensify throughout the night.

A damaging trough in New South Wales, first unleashed across the state's west, left several regions awash.

Despite only being October, Dubbo has now recorded its wettest year in 49 years, with about 882mm recorded up until 4pm today.

While at Bathurst, racing on Mount Panorama was thrown into chaos, after the Top-10 shootout was cancelled due to the torrential downpour.

The regional city has copped more than a month's worth of rain in a few days.



There are more than 60 flood warnings in place across NSW, covering western parts of the state, in the Central West, Hunter, Hawkesbury-Nepean, the South Coast and the Illawarra.

NSW Premier Dominic Perrottet said on Saturday afternoon the state has a situation where dams and rivers are full.

"With heavy rain expected, we ask everybody to continue to be cautious," he said.

"If those flood warnings are in place, please continue to follow instructions, be prepared to be ready if an evacuation is needed.

"Particularly on roads, not just in Sydney but right across the state, please be careful."

However the worst may still be yet to come, with another system expected to move through the state on Wednesday.

"We're only eight days into the storm season and unfortunately, we're seeing flooding continue across NSW," emergency services minister Steph Cooke said.

"It's expected to do so for weeks and months ahead."

Showers to ease briefly

The latest burst of storms is being caused by a developing low pressure system, which will endure well into the evening before dissipating over Sunday and Monday.

Meteorologist Dean Narramore said the trough is being fuelled by tropical moisture, with heavy falls expected to exacerbate flash flooding.

"Widespread areas particularly for our flood-affected areas of inland NSW, (could get) 30-50mm with isolated falls of 80-100mm possible," he said.

"[They system] is going to move eastwards quickly today [Saturday] and expanding, then hit the coast later today into tonight.

"Severe weather warnings current for heavy rainfall and damaging winds from Newcastle all the way down to Ulladulla."

Narramore added the low will take rain offshore Sunday and into Monday, but added another weather system will hit mid-next week.

"Unfortunately the next weather system [arrives] Wednesday to Thursday with a burst of widespread heavy storms," he said.

Narramore's warning comes as residents near the Hawkesbury-Nepean Rivers face a possible fifth flood in 18 months.

The Bureau of Meteorology (BoM) said there's a minor, to moderate risk of flooding along those communities.