In part two of the video, Hail starts falling in the 3 - 4cm range before the big tennis balls of 7 to 8cm start firing down sporadically. Old Northern Road went from a stream of cars to a ghost road in 15 seconds. Any vantage point that had shade had cars parked under it.

I managed to avoid having my windscreen smashed however some of the cars nearby weren't so lucky with rear windows missing on a number of cars.

The last time a storm this big moved through Sydney was back on April 14, 1999. That day a Supercell developed down in the Illawarra and moved North to cause over $1billion damage around the City's East. Today was similar to that day, a Supercell formed south of Penrith and turned left taking the traditional supercell north east track across the western suburbs to the Hills/Upper North Shore. Along the way massive hail up to 8cm in size smashed suburbs in its path with widespread house and car damage reported.Up to 30 people have been reported injured by the storm.

Short 5 minute time lapse of a rotating updraft near Wyong this afternoon. Video was taken around 330pm to 335pm from just south of Wollombi looking south east.

After heading down towards Spring Valley, the core finally catches up and unleashes a barrage of hail on us. At one point visibility was down to a few metres in what felt like driving through a blizzard. Stones ranged from 2 to 3cm