Severe thunderstorms wreak havoc across NSW

A huge system of thunderstorms was rolling thick and fast across NSW on Saturday evening, sparking severe weather warnings for most of the state and descending skies into near-absolute darkness.

Bureau of Meteorology forecaster Jake Phillips said the nature of the storm system was unpredictable, and could see heavy hail, lightning, thunderstorms, and rainfall of between 5 and 30 millimetres spattered across every region.

"There are very widespread storms across most of the state as this low pressure system moves through," Mr Phillips said.

"We just need to watch individual storm cells as they evolve ... it's difficult to say with rainfall because it's quite variable from place to place. [Between 5 millimetres and 30 millimetres] is a wide range I know, but that is just the nature of thunderstorms."

Sydney's western suburbs started seeing heavy rainfall earlier Saturday afternoon, with Bankstown receiving 8 millimetres within the space of just half an hour, while Parramatta received 7 millimetres.

Those readings were set to increase on Saturday evening, but the trough that brought the falls had moved into Sydney's metro areas.

By 7pm, the storm system was expected to be swept out to sea by potentially damaging winds, but another system could come through later on Saturday and persist into early Sunday morning.

"The [weather] warning that's just been updated covers an area from Sydney and Illawarra, up towards the north west slopes to the Queensland border. That warning is for the possibility of large hail, heavy rain and damaging winds," Mr Phillips said.

Mr Phillips said that the Bureau of Meteorology advised people to take precautions when they were travelling in areas with potential floodwaters, and to keep their vehicles undercover.

"There's a few general things that are hopefully common sense for most people that we do advise ... if there happens to be fallen power lines, stay well away from them. Don't walk, drive or ride through floodwaters, and keep clear of creeks and storm drains," he said.

The state's far west suffered the brunt of the thunder and lightning earlier Saturday afternoon.

A 53-year-old man died in Geurie, about 30 kilometres from Dubbo, just after 2pm after being struck by lightning at a recreational ground.

Please explain

Our weekly podcast giving you insight into the stories that drive the nation.

Listen now