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Archive for January 2011

Wave clouds over the UK

For those of you who like a good cloud, today we had some rather impressive wave clouds over the UK. Click here to see some satellite images and plots. The wind pushes air over the hills and as it drops down the other side it starts to oscillate forming a wave pattern.

To make a wave cloud you need three things: a strong inversion, some wind and a hill or two. The radiosonde ascent shows that there is indeed a very strong inversion over the UK which is due to high pressure shown in the synoptic chart. The high pressure system is centred over the UK and as air rotates clockwise around a high pressure system in the Northern hemisphere this leads to Easterly winds over England and Wales. The Western boundary of the hills can be seen clearly in the satellite images.

This isn't a particularly rare occurrence, but the conditions have to be just right. If you have seen some wave clouds let us know.

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