Unusual 'cloud streets' spotted over Oxfordshire and Gloucestershire

News imageBBC Weather Watchers / Major Tom Cloud streets over CirencesterBBC Weather Watchers / Major Tom

Spectacular cloud formations known as 'cloud streets' have been spotted in southern England.

The long streaks of cloud were seen by BBC Weather Watchers in Oxfordshire and Gloucestershire on Thursday evening.

BBC weather presenter Simon King said the clouds are not uncommon in the UK but these stood out against the fading light of the sky.

"Cloud streets are essentially long rows of cumulus cloud aligned in the sky with the wind direction," he said.

News imageBBC Weather Watchers / Mary McIntyre Cloud streets above Tackley in OxfordshireBBC Weather Watchers / Mary McIntyre
The formation was spotted in the sky above Tackley in Oxfordshire
News imageBBC Weather Watchers / Andrew in the Cotswolds Cloud streets in Little Rissington, GloucestershireBBC Weather Watchers / Andrew in the Cotswolds
They were also captured on camera in Little Rissington, Gloucestershire
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BBC Weather presenter Simon King explains how 'cloud streets' form

Warm air on the surface rises, cools and condenses into cloud.

In certain situations a warm layer of air in the lower atmosphere, called an inversion, acts as a lid preventing air from rising any further.

This means at the top of the cloud, the cooler air is forced out horizontally where it will then start to sink back to Earth.

In this area, cloud doesn't form, so it is clear. This all sets up a cylindrical circulation which is parallel with the wind, creating the long row of cloud.

News imageBBC line

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News imageBBC Weather Watchers / PCGN7 Cloud streets above OxfordBBC Weather Watchers / PCGN7
Clous streets were also seen above Oxford

The phenomenon was spotted in Oxford and Tackley in Oxfordshire, and Little Rissington and Cirencester in Gloucestershire.