More than 10,000 homes were without power last night because of storm-related damage – some of the worst affected areas were Swansea, Thornton and Caves Beach.

Lightning caused small fires to spark up in many areas including New Lambton, Dungog, Minmi, Tomago and Tarro.

A car was damaged at Russell Road in New Lambton, police said on Monday, after a lightning strike hit the road before transferring to a pole and into a parked car.

A front window on the car shattered and its electrical systems were damaged, Newcastle police said, while the council was notified about an indentation in the road from the original strike.

Between 7pm and 8pm up to 19mm fell in parts of Newcastle.

Lightning also smashed into parts of the city, a spectacle Facebook user Mark Green captured on video from a city apartment.

"Awesome view of the electrical storm over Newcastle tonight," he wrote.

"My flatmate captured this great vid of a building behind Civic Station getting struck by lightning."

The State Emergency Service received 23 callouts by 8.30pm for fallen trees and other damage.

The wild weather ended quickly with the weather bureau cancelling its severe weather warning within two hours.

Earlier in the day, inland temperatures in areas such as Scone, Tocal, Merriwa and Mangrove Mountain soared above 40 degrees.

Cessnock Airport reached 44.5 degrees at 3.30pm, the hottest temperature ever recorded at this station during the month of November.

It was much cooler at Nobbys where the maximum was 28 degrees. Don White from Weatherwatch said it was ‘‘unusual’’ how much hotter it was inland compared to the coast.

“The sea breezes have been very effective,’’ he said.

The weather bureau said the severe conditions were due to a slow-moving low-pressure trough lying over inland parts of the state with gusty winds ahead of it.

The scorching highs meant a total fire ban was in place in many regions across NSW on Sunday, including the Hunter.