Not out of the woods: NSW smashed by wild weather as more expected to come

More severe storms could pound Australia’s east coast as power outages and potential flood zones continue to pose threats, emergency services are warning.

A man was killed by a fallen tree as heavy rain, winds and lightning lashed much the nation’s southeast on Wednesday.

WATCH THE VIDEO ABOVE: Sydney’s stormy weather set to continue.

The man, believed to be in his 80s, was killed while driving in Cowra as a thunderstorm tore through central NSW before settling over Sydney and the coast.

In the northern Sydney suburb of Mosman, a mother and her two children were inside their home when a large tree came crashing through the roof.

They heard a loud bang but had no idea their roof had been crushed, until they stepped outside.

“You know it’s not even a shock because this has happened before with this tree,” a neighbour told 7NEWS.

“Last year a couple of branches came down and took out power in the whole area.

“It’s so sad, after Christmas, the holidays, now their house is ruined.”

SES received 2000 calls for help across the state, NSW SES commissioner Michael Wassing said.

“Really pleasing to say our 800-plus SES volunteers along with all emergency services partners have already cleared approximately 50 per cent of jobs,” he said.

In Carlingford a roof blew off a family’s home while they sheltered inside.

“We didn’t realise,” Lin Wang said.

“The neighbour called my husband and said ‘Your roof is off.’

“We just heard a big sound, a loud sound, and my kids were crying. I’ve got two boys and they were crying.”

Wassing said the worst storms on Thursday were expected to hit from Port Stephens to South West Rocks and in far-northeast NSW.

“People should prepare themselves now, know their risks and never drive, walk, ride or play in flash flooding should they come across a flooded road or causeway,” he said.

“We know families are still enjoying school holidays, but if you do find yourself camping alongside a river or creek, understand your risk and move to higher ground if required.”

Four people were injured in Wagga Wagga when high winds ripped off the roofs of their demountable huts.

The Bureau of Meteorology monitored a cold front moving across NSW, trailing a mass of warm, humid air on Wednesday.

Senior meteorologist Miriam Bradbury said it created the perfect environment for the widespread and dangerous thunderstorms.

“The system responsible is just hanging on around the coast ... unfortunately for those northern coastlines, it is another couple of wet days with that storm risk continuing,” Bradbury said.

More than 155,000 customers experienced blackouts during the peak of the outages.

Newcastle bore the brunt, with more than 60,000 power users affected, with 31,000 outages in Sydney and 4000 on the Central Coast, distributor Ausgrid said.

Almost 90,000 customers were still without power about midday on Thursday, with Ausgrid blaming more than 300,000 overnight lightning strikes for the outages.

Supply to 55,000 customers in the Blue Mountains, Sydney’s west, the Illawarra region and the South Coast was impacted, with 20,000 since restored, Endeavour Energy said.

The heaviest rainfall came on the South Coast, where 127mm fell at Eurobodalla and 102mm at Barlows Bay in the 24 hours to 9am on Thursday.

Up to 100mm of rainfall is predicted in some areas on Friday.

— With Sarah Keszler