Suburbs across the Inner West have seen extensive flash flooding with reports of some areas experiencing over a metre of water.
Weatherzone said there has been more than 110mm of rain at Marrickville since 9am, including 98mm in just two hours this afternoon.
In Sydney’s west, more than 87mm of rain fell at Toongabbie.
Weatherzone added that today marked the wettest day in 11 months in suburbs including Toongabbie, Baulkham Hills, Prospect, Greystanes, Castle Hill, Bankstown, Canterbury, Sydney Airport, Homebush and Terry HIlls.
Cars and their occupants had to be rescued in Chiswick and Marrickville after floodwaters made it impossible to drive through.
Wolli Creek has been hit particularly hard by the flash flooding as water can be seen reaching the top of car tyres.
Despite the warning from authorities, motorists are continuing to drive through floodwaters.
Commuters hoping to escape the deluge got wet anyway as a bus was flooded in Wolli Creek.
Other city suburbs including Tempe and Sydenham have also been inundated by flash flooding.
The Bureau of Meteorology (BoM) has issued a road weather alert for all Sydney suburbs.
It’s expected thunderstorms and rain should ease in the coming hours however roads will remain wet.
Meanwhile, some Chiswick residents have made the most of the floodwaters, using boogie boards to play in a small puddle.
NSW State Emergency Service (SES) Assistant Commissioner Dean Storey said there have been more than 460 requests for help across Sydney, the Central Coast and the Hunter region.
There have also been 20 flood rescues.
Mr Storey added the majority of the rescues have been due to people attempting to drive through floodwaters.
“Operational activity is probably highest in western Sydney at this point in time, the majority of flood rescues we’re seeing if people driving through flood waters,” he said.
“Sydney overall has been heavily impacted by the rainfall today, the city’s Inner West, and western Sydney are very, very wet, many roads will be flooded as people finish work for the day.”
Mr Storey urged residents to avoid unnecessary driving and not to drive through flooded roads.
“If it’s flooded, forget it, turn around and find another way,” he said.
He also warned the heavy rainfall is expected to continue through the evening.
Central Coast highway closed due to flooding
The Central Coast Highway is closed in both directions at West Gosford, prompting warnings for people to avoid the area, especially with more wild weather on the way.
Severe thunderstorms are forecast again today, and the BoM has issued a warning for a large area stretching from Newcastle to Wollongong.
People in the Sydney, Hunter, Illawarra, Central Tablelands, Lower Western and Upper Western Forecast Districts, have been told to brace for rainfall and damaging winds.
It comes after Sydney was hit by a violent storm cell yesterday, which brought flash flooding, lightning strikes and hail to the western suburbs.
A home was set alight in Glenmore Park after it was struck by a bolt of lightning.
Motorists are urged to avoid driving through flooded roads.