A "very dangerous" weather system has swept across Sydney, sparking a tornado risk in the city’s west.
The weather bureau urgently warned anyone in the area to be careful and watch the radar as the “supercell” rolls through.
After sending out a warning for a particularly severe storm heading towards Fairfield, the Bureau of Meteorology sent out a second alert just minutes later warning of potential tornado activity in western Sydney.
It's the first time Sydney has been issued a tornado warning since 2015.
Explosive storm causes flash flooding
Three cars were left stranded on Military Road near Guildford after being caught in flash flooding.
Authorities are working to rescue the trapped drivers.
Chaos captured online
Dramatic images of the fast-moving and ferocious storm flooded social media, as strong winds, large hail and heavy rain began lashing most of the NSW coast on Thursday afternoon.
“Here it comes,” warned one Twitter user as they posted an ominous picture of the incoming system.
“This could be the end of the world,” posted another man as large hail hammered down.
“Is that a tornado on radar?” questioned another.
Sydney's west was smashed with huge white hailstones that crashed almost horizontally, with one woman posting, "I have never seen hail this big in my life".
Some residents collected hail stones the size of their palm.
Parts of Sydney descended into darkness as the sky exploded with lightning strikes.
"Sydney's sky is a bit angry," one person wrote.
— kerenzo (@sakoyatikoeh) October 14, 2021
A terrifying time lapse captured the sheer strength and scale of the violent system.
But it appeared to pass over quickly, with sunshine breaking through the clouds within 20 minutes in some parts of Sydney.
In a new tweet, the Bureau of Meteorology confirmed "conditions are easing for now".
— Michael (@Blacktown_Lad) October 14, 2021
Wild weather to hit most of NSW coast
The storm is predicted to stretch from Grafton, across Sydney and down to Byron Bay, with flash flooding possible in some locations.
Inland towns such as Armidale, Tamworth and Goulburn could also be in the firing line.
"It will be a little bit hit or miss. Storms often tend to change track as they move towards the coast," BOM's David Wilke said.
"We have a very changeable, dynamic situation so the best bet is really to just keep an eye on the radar."
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