This evening around sunset there was some odd-looking cirrus. The
oddity was that the curvature seemed to be in the vertical plane, not
horizontal. I observed it over a period of 30 minutes from positions
about 1km apart (home to get camera and out again to find a fairly clear
horizon) and that impression persisted. Location East Cambridgeshire.

https://www.flickr.com/photos/54731504@N04/31405011106


The whole scene reminded me of the visiting our open-hearth steelworks
in Glasgow when I was an apprentice. Rivers of molten steel would run
in channels across the floor!


Any help with this would be appreciated.


Mike

On 05/12/2016 19:16, Mike Causer wrote:
This evening around sunset there was some odd-looking cirrus. The
oddity was that the curvature seemed to be in the vertical plane, not
horizontal. I observed it over a period of 30 minutes from positions
about 1km apart (home to get camera and out again to find a fairly clear
horizon) and that impression persisted. Location East Cambridgeshire.

https://www.flickr.com/photos/54731504@N04/31405011106


The whole scene reminded me of the visiting our open-hearth steelworks
in Glasgow when I was an apprentice. Rivers of molten steel would run
in channels across the floor!


Any help with this would be appreciated.


Mike

Looks like it's a fallstreak hole, with the precipitation being blown by
upper winds into that shape. I'm interested if anyone has a better
explanation!

On Monday, 5 December 2016 22:24:15 UTC, Metman2012 wrote:
On 05/12/2016 19:16, Mike Causer wrote:
This evening around sunset there was some odd-looking cirrus. The
oddity was that the curvature seemed to be in the vertical plane, not
horizontal. I observed it over a period of 30 minutes from positions
about 1km apart (home to get camera and out again to find a fairly clear
horizon) and that impression persisted. Location East Cambridgeshire.

https://www.flickr.com/photos/54731504@N04/31405011106


The whole scene reminded me of the visiting our open-hearth steelworks
in Glasgow when I was an apprentice. Rivers of molten steel would run
in channels across the floor!


Any help with this would be appreciated.


Mike

Looks like it's a fallstreak hole, with the precipitation being blown by
upper winds into that shape. I'm interested if anyone has a better
explanation!

The obvious answer is:
Has anyone thought to ask Dawlish.

No?
Baa!

On Mon, 5 Dec 2016 19:16:07 +0000
Mike Causer wrote:

This evening around sunset there was some odd-looking cirrus. The
oddity was that the curvature seemed to be in the vertical plane, not
horizontal. I observed it over a period of 30 minutes from positions
about 1km apart (home to get camera and out again to find a fairly
clear horizon) and that impression persisted. Location East
Cambridgeshire.

https://www.flickr.com/photos/54731504@N04/31405011106

That cirrus is perfectly normal; the curvature always occurs in the
vertical due to the ice crystals falling through layers of air having
differing wind velocities.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
There are more fools than knaves in the world, else the knaves would
not have enough to live upon. [Samuel Butler]

On Tue, 6 Dec 2016 15:02:48 +0000
Graham P Davis wrote:

That cirrus is perfectly normal; the curvature always occurs in the
vertical due to the ice crystals falling through layers of air having
differing wind velocities.

Thank you. I must have never seen it so pronounced before.


Mike