[Sam Jowett]

Please post your photos of unidentified clouds or clouds with no appropriate thread available below. Once identified they will be moved to the relevant threads or new ones created.

This link may help to a certain extent with your cloud identification.

http://amsglossary.a...ss.com/glossary

[Joey.G]

Heres one ive been wondering about for a while, not the big Cu (congestus?) but the sort of high level roll cloud ahead of it. This was a day of some pretty active storms that died out earlier in the evening than normal due to high pressure building from the West, this was taken in the SE as the pressure rise was beginning to unravel the convection that was taking place.

[Andy Ball]

Looks to me like an old upper outflow pattern from a past convective cell

[Pileus]

There had been plenty come through that way, the last of which is just off to the left of this shot

[andre]

Probably cirrocumulus stratiformus and maybe cirrus fibratus(?) or vertebratus(?) but what are we really looking at?

I got this picture from somebody with that question asked. What is going on up there?

 

[Nigel Bolton]

That is a fall streak hole. An aircraft has flown through a layer of Ac that is composed of supercooled droplets, and either by the stirring of the air, or by the temperature of the plane, has caused cloud droplets to freeze.

Once this freezing process is underway, the differenced between saturated vapour pressure over water and over ice cause ice crystals to enlarge, at the same time the water droplets evaporate, a process known as the Bergeron Findeisson process, responsible for most of the rain that falls in the UK.

What can be seen is an area where ice crystals are growing, hense the feathery, cirrussy appearance of the ice crystal cloud, surrounded by clear air, where the super cooled water droplets have evaporated. This process is most efficient at temperatures of around -10C.

N.

[RobN]

Here's another fallstreak hole, photographed in twilight 01/08/2011 over South Cambs.

[4wd]

Asperatus

[Uskys]

Pileus, Brecon Beacons 30th April 2012

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