What caused the 300km rolling cloud over New South Wales today?

What caused the 300km rolling cloud over New South Wales today?

A series of rolling clouds could be seen stretching more than 300km over eastern New South Wales on Tuesday afternoon, from Bowral to Nelsons Bay and beyond.

The satellite image below shows the series of parallel clouds settling over eastern New South Wales in the early afternoon.

The clouds were even more captivating from the ground, stretching from horizon to horizon cutting a long path beneath patches of higher cirrus clouds.

Video: Tuesday rolling clouds seen from Crackneck Lookout in Bateau Bay, New South Wales.

The roll clouds were produced by atmospheric gravity waves that formed over eastern New South Wales on Tuesday morning. These invisible waves in the atmosphere caused elongated areas of rising air that cooled enough to produce parallel bands of clouds. These roll clouds then moved eastwards and passed over Sydney, Newcastle and surrounding areas of eastern New South Wales.

Image: Clouds break over Sydney on Tuesday afternoon. Source: Stella Sharwood

The roll clouds that passed over eastern New South Wales on Tuesday were similar to the famous bluebell clouds that develop near the Gulf of Carpentaria in northern Australia.