Bizarre cloud shelf delights NSW holiday traffic

Holiday traffic on the New South Wales south coast has pulled over to witness a bizarre cloud formation over Gerringong.

The cloud shelf formed just after 2pm amid humid conditions, delighting onlookers.

One local told 9News, ‘I’ve never seen anything like it.”

Weatherzone meteorologist Joel Pippard says the phenomena usually coincides with thunderstorm activity, admitting the clear blue skies surrounding this particularly lone cloud are “less common.”

Mr Pippard told 9NEWS, a very strong inversion layer about 500 metres above the surface is what the cloud is trapped under.

It has been brought on by a southerly change which is moving up the coast, with the temperature in nearby Kiama dropping from 25 degrees to 21 as it moved through.

“Warm air rises, especially with cool air behind it – as in this instance,” explained forecaster Mr Pippard.

“As it does that, it cools and the water condenses - that’s the cloud you see. Because it’s so humid, the moist air becomes cloud,” said Mr Pippard.

Thanks to the toasty weather being experienced by much of the country this week, the air is so warm thunderstorms are finding it hard to form.

The southerly should dissipate around the northern suburbs of Sydney around 8pm, before turning back to a northeasterly wind. 

The cloud itself disappeared around 4pm as the change weakened.