Rare. Polar Stratospheric Clouds over UK

[Balance]

Social media UK is awash with amazing cloud photos due to an unusual event. Of course, a certain crowd are really going to town over "chemical skies".

POLAR STRATOSPHERIC CLOUDS SEEN OVER IRELAND FOR THE FIRST TIME IN 21 YEARS

Polar stratospheric cloud
The stratosphere is very dry; unlike the troposphere, it rarely allows clouds to form. In the extreme cold of the polar winter, however, stratospheric clouds of different types may form, which are classified according to theirphysical state and chemical composition.

Due to their high altitude and the curvature of the surface of the Earth, these clouds will receive sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn or after dusk.

http://donegalweatherchannel.com/20...-over-ireland-for-the-first-time-in-21-years/

They say they might be visible again tomorrow so I'll be checking sunset and sunrise.

Enjoy.

















Read more: http://metro.co.uk/2016/02/02/these-rainbow-clouds-are-beautifully-haunting-5657528/#ixzz3z1L8jgrK

 

[Trailblazer]

I was just about to post a thread about this. Unfortunately it was overcast here last night so I didn't get to see them, but the conditions may be suitable for a few days yet.

 

[cloudspotter]

They were amazing this morning but unfortunately I only had my phone camera with me. I'm a little puzzled about the display yesterday morning though. At first I thought it was a particularly good display of iridescent clouds but then I saw all these reports of nacreous clouds but I still wasn't convinced.

1. I could see the clouds before they started to take on colour and they just looked like normal lenticular cirrocumulus
2. The colour in them only started to show as the sun started to rise
3. When I was finally in a position where I could get a half decent photo there was only a small patch left next to the sun and I had to position myself so the sun was blocked out to take the picture.

If anyone could help clear this up for me I'd be much obliged

 

[Trailblazer]

Incidentally the potential for this display was flagged up several days ago on a weather forum I read:

 

[Balance]

If anyone could help clear this up for me I'd be much obliged

https://en.wikipedia.org/wiki/Polar_stratospheric_cloud

 

[cloudspotter]

https://en.wikipedia.org/wiki/Polar_stratospheric_cloud

I know but

They are best observed during civil twilight when the sun is between 1 and 6 degrees below the horizon.

See point 3

 

[Balance]

Sorry, didn't (still don't) understand point three.

 

[cloudspotter]

Sorry, didn't (still don't) understand point three.

Sorry I didn't make myself clear. It seems that you would normally expect to see nacreous clouds when the sun is below the horizon, in the two hours before the sun comes up. Iridescent clouds are usually seen close to the sun and are best viewed when the sun is blocked as it was when I took my picture

 

[Trailblazer]

They were amazing this morning but unfortunately I only had my phone camera with me. I'm a little puzzled about the display yesterday morning though. At first I thought it was a particularly good display of iridescent clouds but then I saw all these reports of nacreous clouds but I still wasn't convinced.

1. I could see the clouds before they started to take on colour and they just looked like normal lenticular cirrocumulus
2. The colour in them only started to show as the sun started to rise
3. When I was finally in a position where I could get a half decent photo there was only a small patch left next to the sun and I had to position myself so the sun was blocked out to take the picture.

If anyone could help clear this up for me I'd be much obliged

AFAIK nacreous clouds only really show up when the sun is below the horizon. So maybe there were some normal iridescent clouds around too?

 

[cloudspotter]

BTW I've already been out and spotted a little colour starting to appear in the sky

 

[cloudspotter]

AFAIK nacreous clouds only really show up when the sun is below the horizon. So maybe there were some normal iridescent clouds around too?

This was my thought. I've never seen nacreous before this morning so I had nothing to compare it to

 

[Mick West]

When I saw the first report of these clouds on Facebook it was with the sun above the horizon, so I assumed it was just a normal iridescent cloud, so I "corrected" the person who said they were nacreous. Then the photos started flooding in, oops.

 

[Balance]

I just realised I posted this in the wrong forum. Would it be best moved to Photos of Clouds or somesuch? If moved, please delete this post and thanks for your understanding.

 

[Trailblazer]

This was my thought. I've never seen nacreous before this morning so I had nothing to compare it to

I have seen them once, but 20 years ago. They appear much more luminous than iridescent clouds, as they are usually seen against a quite dark twilight sky. Compare the pictures on this thread (which are genuine nacreous clouds) with this, for instance, of iridescent clouds:

If you see them near the sun in the sky, I would say there are very unlikely to be nacreous.

 

[cloudspotter]

I have seen them once, but 20 years ago. They appear much more luminous than iridescent clouds, as they are usually seen against a quite dark twilight sky. Compare the pictures on this thread (which are genuine nacreous clouds) with this, for instance, of iridescent clouds:

If you see them near the sun in the sky, I would say there are very unlikely to be nacreous.

Yeah I'm fairly convinced that it was iridescent I saw on Monday morning. Nacreous this morning though

 

[Galan]

I just realised I posted this in the wrong forum. Would it be best moved to Photos of Clouds or somesuch? If moved, please delete this post and thanks for your understanding.

It's ok. I asked Mick about it. Getting the feel for things here.

 

[Mick West]

I just realised I posted this in the wrong forum. Would it be best moved to Photos of Clouds or somesuch? If moved, please delete this post and thanks for your understanding.

I moved it into the image sub-forum, but it's really fine.

 

[Trailblazer]

Yeah I'm fairly convinced that it was iridescent I saw on Monday morning. Nacreous this morning though

I'm not so sure now. There are three different phenomena that have been observed recently:

Iridescent clouds (cirrus, around 30,000ft)

Nacreous clouds (PSCs) (about 50-80,000ft)

Noctilucent clouds (about 250,000ft)

I was thinking of noctilucent clouds when I said they can only be seen with these below the horizon. Nacreous ones can be seen during the daytime but are more vivid during twilight.

 

[cloudspotter]

I'm not so sure now. There are three different phenomena that have been observed recently:

Iridescent clouds (cirrus, around 30,000ft)

Nacreous clouds (PSCs) (about 50-80,000ft)

Noctilucent clouds (about 250,000ft)

I was thinking of noctilucent clouds when I said they can only be seen with these below the horizon. Nacreous ones can be seen during the daytime but are more vivid during twilight.

This is the tail end of what I saw on Monday morning. Very close to the sun which I was trying to block out

 

[cloudspotter]

This was Tuesday morning

And Tuesday evening

 

[tadaaa]

The UK met office had an explanation these on their blog yesterday


pearl' clouds enthrall skywatchers
2022016
Over the past few days, conditions in the upper parts of the atmosphere have allowed us to be treated to a rare glimpse of Nacreous Clouds.

What are they?
Found in the lower stratosphere, these clouds are mainly seen over polar regions in winter, where very cold air – minus 80˚C and lower – condenses the small amount of water vapour present into tenuous clouds. These clouds are normally found at altitudes of around 20 km.

http://blog.metoffice.gov.uk/2016/02/02/mother-of-pearl-clouds-enthrall-skywatchers/

 

[Galan]

Support for climate change? Cooling of the atmosphere and the shrinking of the boundary of the upper atmosphere? Very pretty in any case.

 

[Gridlock]

Stuff like this is how deity-worship got started

Amazing images.