Menai was among areas where flood rescues were reported during the severe electrical thunderstorm that hit Sydney last night.
Many roads were flooded by torrential rainfall, accompanied by dramatic bursts of lightning and thunder claps.
The Princes Highway at Blakehurst was almost at a standstill with two of three southbound lanes closed.
The Sydney storm cell was part of a long line of severe thunderstorms that moved through the Sydney basin, Hunter and Illawarra.
A spokeswoman for the weather bureau said the city looked like it had been hit with one severe storm cell, while the Camden and Illawarra areas saw multiple cells which increased the risk of flash flooding in those areas.
More than 6400 homes across Sydney also experienced power outages, according to Ausgrid at 8.30pm. Emergency crews were being sent out to restore power safely.
The Bureau of Meteorology recorded 40 millimetres of rain in just 30 minutes at Auburn during the peak of the storm.
Lucas Heights recorded 40mm between 7pm and 8.30pm with more than 20mm falling in the first half-hour. At Sydney Airport 23mm was recorded between 8.30pm and 9pm
The Bureau is forecasting another 8 to 20 millimetres of rain to fall in Sydney on Friday.