Lightning strikes Sydney Tower during massive storm

Sparks could be seen flying from more than a kilometre away when lightning struck Sydney Tower during last night's destructive thunderstorm.

Surry Hills man Keith Walsh was filming from his inner-city apartment just before 10pm when the lightning bolt hit Australia's tallest building.

"It was extremely loud and very bright," he told the Sydney Morning Herald.

"There was a spark and then the actual light on the tower flickered slightly, it turned off. It was very frightening."

PHOTOS: Wild weather in NSW

Eastern NSW has been inundated overnight, with heavy falls causing flash flooding in Bexley, Lewisham, Summer Hill and Bardwell Park.

The southern Sydney suburb of Sans Souci has received its highest rainfall in 23 years, with 141mm on the gauge since 9am yesterday.

Meanwhile, snow has fallen in the Blue Mountains and Central West, with the Great Western Highway closed between Katoomba and Bathurst.

Blackheath and Lithgow have seen the heaviest of snowfalls, both areas where such weather is highly unusual.

The storm front is currently moving north and Newcastle is tipped for rough weather this morning.