Thousands of homes across Sydney and the Illawarra remain without power as crews continue to work through complex repairs after an intense burst of thunderstorms overnight.
A second wave of storms was predicted to batter Sydney again, but the Bureau of Meteorology has revised down the likelihood of wild weather on Saturday night.
Endeavour Energy said it expects to work into the night to restore power to 2500 customers, with many of them to spend a second night in the dark.
"There has been nearly 400 electrical hazards caused by this storm, mainly from trees falling across powerlines in the strong winds," Endeavour Energy said in a statement.
Nine people were rescued from floodwaters and more than 40,000 properties lost power after the storms across Sydney and the Illawarra and the Hunter regions on Friday evening.
Flash flooding in Parramatta and other parts of western Sydney turned intersections to lakes and led several drivers to ask for SES help to get them out of their cars.
Guildford copped 61 millimetres of rain, including 47mm in just 30 minutes while Sydney Olympic Park received 40mm in the 40 minutes to 7pm.
The SES was responding to more than 500 jobs, mainly for leaky roofs and trees down.
Organisers of the Tropfest short film festival have scrambled to find a different location for the event at the eleventh hour after wild storms damaged a stage and screens.
The festival will now be held in an alternate location within Parramatta Park on Saturday afternoon.
"While the site we had built in The Crescent at Parramatta Park cannot be used, we are fortunate that Rose Lawn, a safe, suitable location adjacent to the original site will be ready for fans to enjoy today," event director Paul Kind
said in a statement.
Parramatta was one of the hardest-hit suburbs, with the majority of outages and calls to the SES coming from the area.
Two schools were badly damaged, with significant repairs needed for roofs at Parramatta East Public School and Parramatta North Public School, an SES spokeswoman said.
More than 1000 calls were made to the SES, with roughly half of them resolved by Saturday afternoon, said Vanessa Hutchinson, SES Coordinator Duty Operations.
"We're moving as fast as we can," Ms Hutchinson told AAP. "We'll be working on jobs over the next few days."
Endeavour Energy spokesman Peter Payne said the scale of damage and complexity of repairs meant they could not provide an exact restoration time for all customers.
"There's a lot of hard work to be done, there's a lot of damage from this storm," Mr Payne told AAP. "We appreciate people's patience."
In the city's north and east, some 15,000 properties on Ausgrid's network went dark but it was expected power would be restored to all by Saturday night.
Video posted on social media showed flash flooding in Parramatta, with water inundating cars.
"Never approach fallen wires, always assume they're live, stay at least 8 metres away and report them to us on 131388," Ausgrid said in a statement.
Another video posted on Twitter from Putney Hill showed power lines sparking as heavy winds gushed in the background.
Train and airport services have also been affected by the wild weather.
At 7.30 pm on Friday, Sydney Trains announced some services were delayed after lightning damaged equipment at Blacktown, while social media users posted photos of water leaking inside the train carriage.
A Sydney Airport spokesperson said 30 flights had been delayed due to the weather, with travellers facing delays of up to 90 minutes.
The spokesperson advised anyone travelling via the airport to check with their airline in advance.
The NSW Rural Fire Service has warned that the strong winds would increase fire risk across parts of the state over the weekend, forecasting "very high fire danger".
Meanwhile, people in the Mid North Coast and parts of the Hunter and North West Slopes have been warned of a severe thunderstorm predicted to bring damaging winds and large hailstones on Saturday night.
