On 02/02/2016 12:23, David Mitchell wrote:
On Tuesday, February 2, 2016 at 12:11:50 PM UTC, Freddie wrote:
Martin Brown Wrote in message:
On 01/02/2016 18:14, Col wrote:
On 01/02/2016 18:11, Trevor Harley wrote:

Behind the view of flying trees and roofs there was quite a good
display of iridescent (I think they are) clouds this evening.

http://trevorharley.com/trevorharley/Weather.html


Saw something very similar here towards the west.

It appears the strong winds have punched some water vapour up into the
stratosphere.

I think they have formed because the stratosphere is much colder
than normal at the moment, rather than additional water vapour
being added to it.

I think it requires both conditions to be met before you see any. The
stratosphere is normally too dry for PSCs to form even when cold enough.

Incidentally the ozone levels over Uccle have crippled by 100 DU in the
last few days so it is definitely widespread and stratospheric clouds.
It is only about 20 away from hitting their lowest baseline of 200DU.

http://www.meteo.be/meteo/view/nl/12...ratosfeer.html

I presume the location of the most visible clouds is related to the
structure of lee waves from the Pennines.

Yes Martin they are still there. Skies have cleared somewhat and with
them being in the Southern half of the sky and a low sun,
they are quite hard to spot, unless you know they're there.

They were still fairly colourful - especially on the leading edge at
lunchtime but have been thickening up since then and are now a mottly
white with hints of colour but still obviously sculpted by the wind.

I am hoping they will persist into the evening when I will be able to
take some better pictures with a proper camera and tripod rather than
handheld from a moving car with a mobile phone.

I was amazed when I spotted them early this morning.

--
Regards,
Martin Brown