Residents in Sydney’s south-west are warned to prepare to evacuate as unrelenting rainfall causes flash flooding and chaos across the city. 
Sydney Olympic Park and North Parramatta each experienced 118mm of rain, while Hornsby had 116mm and Auburn saw 115mm in the 24-hour period ending at 9 am today.
Sydney Observatory Park saw 72mm and Sydney Airport saw 60mm.
The severe rainfall overnight and into today has prompted flash flooding across parts of the city.
People residing in low-lying areas along Cobbity Road and Cut Hill Road in Cobbitty are being advised to get ready to evacuate due to potential flooding from the Nepean River.
“If you remain in the area, you may become trapped without power, water, and other essential services,” NSW SES said.
“It may be too dangerous for NSW SES to rescue you.”
Flood warnings are also currently issued for Cooks River at Tempe Bridge, Georges River at Milperra and Liverpool, and Hawkesbury River at Windsor and North Richmond, with authorities urging residents to remain updated.
Gronos Point residents are urged to prepare to isolate due to flooding.
The inundation and strong winds shut down runways at Sydney Airport this morning, which is causing flow-on delays to flights.
“As a result of single runway operations earlier this morning, there are some delays,” a Sydney Airport spokesperson said.
“Sydney Airport recommends passengers check with their airlines regarding the status of their flight.”
Several Qantas and Virgin flights out of Sydney have been impacted by delays and cancellations.
The flood emergency in NSW’s Mid-North Coast has also impacted flights into Newcastle, Coffs Harbour and Port Macquarie.
Port Macquarie Airport has been shut.
On the train lines, floodwaters covered some tracks and shut down services.
The North Shore Line between Central and Town Hall was earlier impacted by flooding but is now returning to normal.
The Leppington and Inner West, Liverpool and Inner West and Airport and South lines all faced delays and impacts to services due to flooding at Bardwell Park and Bexley North.
That flooding is now beginning to recede on the tracks at Bardwell Park and Bexley North and services are returning to normal on the Airport and South Line.
The Eastern Suburbs and Illawarra line is still experiencing delays due to flooding near the tracks at Oatley and a train requiring repairs at Bondi Junction.
“We’ll have engineers undertaking assessments in the next hour or two, we are hoping to have that line reopened later today,” Sydney Trains Chief Executive Matt Longland said.
Sydney officials were expecting big crowds in the city tonight for the first showing of the 23-day Vivid Festival but are now urging people to consider visiting another day.
“We ask you to consider that services later this evening may be disrupted due to weather conditions,” Transport for NSW Coordinator General Howard Collins said.
The Central Coast and Newcastle Line is also affected due to flooding at Cockle Creek and the Hunter Line due to flooding at Sandgate.
Dramatic scenes are coming out of Parramatta Wharf, where flooding and water levels are climbing the opal gates. 
Motorists are advised to avoid non-essential travel in flood-affected areas as a number of road closures are in place across Greater Sydney.
Here is a list of the closures as of 2pm:
- Sackville Ferry
- Lower Portland Ferry
- Springwood Road at Yarramundi Bridge.
- Cambridge Avenue between Canterbury Road and Moorebank Avenue at Glenfield
- Riverside Drive between Delhi Road and Lane Cove Road at North Ryde
- Ku-Ring-Gai Chase Road at North Turramurra
- Wisemans Ferry Road at Cattai Creek
- Cattai Road between Eldon Street and Millers Road at Pitt Town
- Pitt Town Road at McGraths Hill
- Wakehurst Parkway at Oxford Falls
- Audley Weir in Royal National Park
