A man was killed by a fallen tree as heavy rain, winds and lightning lashed a swathe of the nation's southeast on Wednesday.
The driver, believed to be in his 80s, was killed in Cowra as a thunderstorm tore through central NSW before settling over Sydney and the coast.
Another four people were injured in Wagga Wagga when high winds ripped off the roofs of their demountable huts.
Storms and rain on Thursday are expected to be less severe, but people are being asked to monitor forecasts and steer clear of danger
NSW State Emergency Service commissioner Mike Wassing warned holidaymakers in the state's north to steer away from camping near rivers and creeks with up to 80mm of rain expected to drop on Friday.
"If you're camping near rivers, now's the time to move away from those local water sources into a safe location until we see this weather dissipating," he said.
The Bureau of Meteorology monitored a cold front moving across the state, trailing a mass of warm, humid air on Wednesday.
"Which made the perfect environment for these widespread, significant, dangerous thunderstorms," senior meteorologist Miriam Bradbury told AAP.
"What's remarkable about what we've seen over the past 24 hours is just how widespread the storms have been."
The wet weather will continue in the NSW Hunter region and further north on Thursday.
"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," Ms Bradbury said.
SES crews received more than 2250 calls and responded to more than 1800 incidents in the 24 hours to 5am on Thursday, predominantly for fallen trees and property damage.
High winds ripped off roofs. (HANDOUT/NSW STATE EMERGENCY SERVICE)
Minor flood warnings have been issued for a series of rivers in northern NSW, as well as the Hunter and Central Coast regions.
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, as well as 31,000 in Sydney and 4000 on the Central Coast, distributor Ausgrid said.
Almost 90,000 customers were still without power shortly before midday on Thursday, while Ausgrid blamed the more than 300,000 overnight lightning strikes for the outages.
Mother Nature put on quite a show last night! 🌩�— NSW SES (@NSWSES) In the last 24 hours, the NSW SES responded to 1844 incidents across the state.Rain is expected to continue through Saturday. Stay updated via the Hazards Near Me app or the NSW SES website (https://t.co/BCnxAdOSBj) pic.twitter.com/WLxbqwfa26January 15, 2025
Supply to 55,000 customers in the Blue Mountains, Sydney's west, the Illawarra region and 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.
Friday could see the worst of the rain, including falls of up to 100mm predicted in some areas.
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