UPDATE - 6:30pm:
The severe thunderstorm warning for Sydney has been cancelled.
The Bureau of Meteorology release this statement:
Severe thunderstorms in the warning area have temporarily eased.
Further severe thunderstorms are still possible.
The situation is being closely monitored and further detailed warnings will be issued as necessary.
A regional thunderstorm warning is current.
Earlier, there was flash flooding across parts of Sydney, with social media showing a lot of water at Strathfield station.