Australia Weather News

Emergency services have rescued several people trapped in floodwaters across Sydney as a wild thunderstorm hits the city and large parts of NSW.

The severe thunderstorm hitsouthern parts of the state overnight and early this morning before travelling towards Sydney.

The storm dropped about 80 millimetres of rain across the city in an hour and a half.

It caused widespread flash flooding and briefly closing major roads.

The NSW State Emergency Service (SES) responded to more than 550 incidents across the state, with more than 300 call-outs across Sydney's inner and western suburbs.

SES teams responded to more than 20 flood rescues across Sydney Metro early Monday afternoon, mostly drivers caught in the flood waters.

The threat posed by wild storms is starting to ease as the storm travels further north.

A severe weather alert issued around lunchtime has been downgraded, with the threat reduced in areas including Sydney City, Parramatta, Hornsby, Bondi and Terrigal.

Icy morning in southern NSW

Earlier today, the storm front forced the closure of several schools in the Riverina region, where one person was rescued from floodwater at Harden, near Cootamundra.

Nearly 50 millimetres of rain fell in the space of 30 minutes in Murrumburrah, which caused flash flooding in the town centre.

Harden Post Office licensee Michelle Gallo said the storm hit the area at about 6am.

"The force of it ended up smashing windows in the post office, gutters overflowed, we've got water damage coming through walls," she said.

"The road out the front was probably about knee-high, a metre under water and ice."

Ms Gallo said residents and the council were working together to clean up the town, which looked "like Canada".

"We've got council out there doing a fantastic job, cleaning footpaths, pulling the ice away from their doors, using the loader to scrape the road so people can actually get through," she said.

"At one point we had four cars that were bogged in the main road."

Ms Gallo said she had not seen a storm so severe in more than 75 years.

"We are open as usual, unfortunately the only business in the main street that is open," she said.

"We haven't been able to get out of town to do our deliveries, but the mail in-house is here, waiting for people to collect it."

Scores of calls for help

SES volunteers have been helping Harden residents clean up debris and other storm damage.

SES media coordinator Emily Barton said local teams responded to more than 80 calls for assistance in the past 24 hours.

"Most of the jobs in Harden are mainly for damaged roofs due to hail, rain and debris, lots of trees down," she said.

"At about 7:08am, we were called to a flood rescue and that was for one person trapped in a vehicle.

"NSW SES flood rescue operators attended the scene and that person is now out of the vehicle safely."

Ms Barton said the clean-up would "continue throughout Monday and potentially into the early hours of Tuesday morning".

"We are expecting quite widespread unsettled conditions across NSW this week, so people should monitor the Bureau of Meteorology," she said.

More storms predicted

Ausgrid and Endeavour Energy reported more than 12,000 customers in the Sydney area were without power.

The weather bureau said the low-pressure system which has caused the wild weather is expected to remain over NSW into Tuesday. 

Severe thunderstorms are again possible across much of NSW with flash flooding a risk across the east, including Sydney. 

There is also the chance of isolated rainfall totals of up to 120mm within six hours on the South Coast.

The showers and thunderstorms are expected to continue to impact the east coast until Saturday.