Huge storm smashes Sydney with torrential rain with ‘large hail’ warning issued

Severe thunderstorms have begun across greater Sydney, with the city’s west already engulfed in wild weather.

Residents in parts of NSW, the ACT and Victoria were put on storm alert on Thursday, with flash flooding possible.

The slow-moving thunderstorms began hitting those in northeast Victoria and southern NSW on Thursday morning, with the system worsening and moving north over the course of the day.

The thunderstorms are caused by a moisture-laden air mass interacting with a higher-level trough, according to WeatherZone meteorologist Ben Domensino, who described it as an “ideal environment” for towering clouds.

The storm rages over Sydney

A huge storm plank is pictured heading out to sea over the Princes Highway in Sydney's Kogarah

A huge storm plank is pictured heading out to sea over the Princes Highway in Sydney’s Kogarah

“Lightning should become more widespread during the day and into the evening as warmer air at the surface further fuels this storm-ready environment,” he said.

Sydney, Melbourne and Canberra are all in the firing line for rain, but the worst thunderstorms are likely to be confined to inland NSW.

“Any thunderstorms that form across Vic, NSW and the ACT on Thursday will bring an increased risk of flash flooding due to weak steering winds, causing the storms to move slowly,” Mr Domensino warned.

‘Although heavy rain is the biggest threat, large hail and damaging winds are also possible.’

The south-east will be lashed by rain this week, with inland regions of NSW and Victoria well soaked.

Major thunderstorms are already starting to affect northeastern Victoria and southern NSW.  Photo: WeerZone

Major thunderstorms are already starting to affect northeastern Victoria and southern NSW. Photo: WeerZone

The circumstances will be one "ideal environment" for thunderstorms and towering clouds.  Photo: WeerZone

Conditions will create an “ideal environment” for thunderstorms and towering clouds. Photo: WeerZone

Albury on the NSW-Vic border received 41mm of rain overnight, breaking a three-week dry spell, while Braidwood, east of Canberra, saw the heaviest daily rainfall at 31.6mm. knew for a year.

Sky News meteorologist Alison Osbourne warned that more than 100mm could fall in areas north of Newcastle and bushfires in Queensland could also receive rainfall.

“It’s also good news especially in fire-affected areas, with widespread falls likely exceeding 25 to 30 millimeters,” she said.

Fortunately, most of the rain will clear in areas south of Newcastle on Saturday, with temperatures in Sydney likely to reach 30 degrees Celsius this weekend.

Melbourne will have a much warmer day on Friday at 31 degrees Celsius, before cooling to 18 degrees Celsius on Sunday.