Another Big Thunderstorm Has Hit Sydney

Less than 24 hours after the big storm that left many homes in Sydney without power, another big thunderstorm has hit.

Visibility on the M1 is at a minimum, with thick cloud and heavy rain.

Graeme Britton from weatherzone said that a low pressure system is generating damaging conditions across Sydney.

"It's looking to affect north-western parts of the city over the next hour," he said.

"It's moving in from the north-west, and there's a chance of giant hailstones, heavy rain and damaging winds."

The state emergency service has received 900 calls for help as the system moves through eastern NSW.

"It is possible we'll see further severe storms into the evening, and possibly into the early hours of the morning," Phil Campbell from the SES said.

"We are now asking people around Sydney to make sure they've parked their cars undercover and bring children and pets indoors as storms approach.

"And if you do suffer damage from the storms, call the SES on 132 500."