Strange Cloud formation over Waterford 02-06-10

Roen

Hi all,

**Mods, if pics are too big just let me know**

Just wondering if anyone had any input as to what kind of formation this is.

It was over Waterford for approx 45 mins today, 02-06-10. I've never seen one before and am wondering is there a name on it.
Unfortunately when the formation was at it's most 'unique' I only had a crappy phone with me and by the time I got home to the big guns it had dissapated by and large.

In the first pic the ring of cloud was much more clearly defined that it would appear due to the modest nature of my phone. Note the sun dog in the lower left of the ass cheek part of the formation. It was visible for about 25 mins I'd say.



In the second pic I captured as much of the surrounding cloud possible so I made a rather large stitch. The formation had largely broken up by the time I got home though

Su Campu

That's a fallstreak hole, nicely spotted!

In the layer of cirrocumulus cloud, the water is supercooled, meaning it's below 0°C but still liquid. Some random process, possibly some turbulence, passing plane, etc. has initiated freezing at a certain point, and this has quickly spread, causing the now frozen water droplets to fall out of the layer they were in, leaving the hole behind. (It's a bit like that hole in the street in Guatemala!)

What time was it taken at?

Roen

Thank you very much Su Campu,

I have to admit it wasn't too hard to spot as it was quite large indeed although it would be hard for me to judge distances or scales.

The first pic was taken at 18:44 and the second at 18:57.

The part that struck as me most unusual was that there was a definite circular motion in the central portion of the hole. It's more obvious in the first picture where you can see the opposite rotation of the two sides of the inner part meeting in the lower part of the hole and folding in on themselves and being pushed toward the middle area.

**EDIT** After reading up a bit I could be talking through my hat here. **EDIT**

Cheers once more for the reply.

Clear Skies (or cloudy ones...whatever floats your boat )
Ronan.

Duiske

I assume this is the same thing Roen seen ? Picture was taken by my bro in New Ross about 9pm.

kobolt

Same cloud with rainbow inside view from waterford

http://www.facebook.com/photo.php?pid=1285387&l=c31dea5d00&id=1344850761

Roen

Yep that's the one alright, could be seen over south Kilkenny and now confirmed in New Ross too.
Is the coloured patch of light known as a sundog?

Su Campu

Roen wrote: »

Yep that's the one alright, could be seen over south Kilkenny and now confirmed in New Ross too.
Is the coloured patch of light known as a sundog?

Yes, and it's proof of the presence of ice crystals in the inner part of the pattern. The rest of the layer is supercooled liquid, which does not cause sundogs.

Roen

Thanks once more Su!
i've actually seen more sundogs in the past three years than I have in the rest of my life. And I wasn't born today or yesterday!

digme

I seen it in cork too around 7 or 8 clock, looked mad.
Nice pictures op.

purplestar1986

We saw three in a row in Tullow around 7 or 8 aswell! Wish I'd taken a pic now.

Aruba08

great pics OP.

I was watching it over Dunmore East and its great to get an explanation

Su Campu

Here's an interesting article on those punch hole clouds and how in certain cases planes can cause snowfall from them.

http://journals.ametsoc.org/doi/pdf/10.1175/2009BAMS2905.1

Abstract
The production of holes and channels in altocumulus clouds by two commercial turboprop aircraft is documented for the first time. An unprecedented data set combining in situ measurements from microphysical probes with remote sensing measurements from cloud radar and lidar, all operating from the NSF/NCAR C130 aircraft, as well as ground-based NOAA and CSU radars, is used to describe the radar/lidar properties of a hole punch cloud and channel and the ensuing ice microphysical properties and structure of the ice column that subsequently developed. Ice particle production by commercial turboprop aircraft climbing through clouds much warmer than the regions where contrails are produced has the potential to modify significantly the cloud microphysical properties and effectively seed them under some conditions. Jet aircraft may also be producing hole punch clouds when flying through altocumulus with supercooled droplets at heights lower than their normal cruise altitudes where contrails can form. Commercial aircraft therefore can generate ice and affect the clouds at temperatures as much as 30°C warmer than the −40°C contrail formation threshold temperature.

demonspawn

Su Campu wrote: »

That's a fallstreak hole, nicely spotted!

In the layer of cirrocumulus cloud, the water is supercooled, meaning it's below 0°C but still liquid. Some random process, possibly some turbulence, passing plane, etc. has initiated freezing at a certain point, and this has quickly spread, causing the now frozen water droplets to fall out of the layer they were in, leaving the hole behind. (It's a bit like that hole in the street in Guatemala!)

What time was it taken at?

"Fallstreak hole" eh? Do me a favor, search for fallstreak hole on this NSDC World Data Center for Meteorology and tell me why they don't have that term in their database. In fact, search for fallstreak hole, fallstreak cloud, hole punch cloud...whatever you want, it's not there. It's not what you claim at all. Please provide a link that uses the term fallstreak hole and explains what it is.

The only reference the "fallstreak hole" has is to some cloud watching society.

TheMilkyPirate

demonspawn wrote: »

"Fallstreak hole" eh? Do me a favor, search for fallstreak hole on this NSDC World Data Center for Meteorology and tell me why they don't have that term in their database. In fact, search for fallstreak hole, fallstreak cloud, hole punch cloud...whatever you want, it's not there. It's not what you claim at all. Please provide a link that uses the term fallstreak hole and explains what it is.

The only reference the "fallstreak hole" has is to some cloud watching society.

http://en.wikipedia.org/wiki/Fallstreak_hole

Lumi

demonspawn wrote: »

"Fallstreak hole" eh? Do me a favor, search for fallstreak hole on this NSDC World Data Center for Meteorology and tell me why they don't have that term in their database. In fact, search for fallstreak hole, fallstreak cloud, hole punch cloud...whatever you want, it's not there. It's not what you claim at all. Please provide a link that uses the term fallstreak hole and explains what it is.

The only reference the "fallstreak hole" is to some cloud watching society.

You can't have looked very hard!
Even Wikipedia has references to 'Fallstreak holes' and a quick search on Google Scholar will reveal the existence of numerous academic papers relating to the phenomenon.

Here's one to mull over
http://arxiv.org/ftp/arxiv/papers/0907/0907.4302.pdf

Su Campu

demonspawn wrote: »

"Fallstreak hole" eh? Do me a favor, search for fallstreak hole on this NSDC World Data Center for Meteorology and tell me why they don't have that term in their database. In fact, search for fallstreak hole, fallstreak cloud, hole punch cloud...whatever you want, it's not there. It's not what you claim at all. Please provide a link that uses the term fallstreak hole and explains what it is.

The only reference the "fallstreak hole" has is to some cloud watching society.

So because it isn't mentioned on one site (that is actually about observational and climatic data) then it doesn't exist?

Plenty of official references to it here
http://www.nws.noaa.gov/glossary/index.php?letter=f
http://apod.nasa.gov/apod/ap040112.html
http://amsglossary.allenpress.com/glossary/search?id=virga1

Duiske

This thread will shed a bit of light on why Demonspawn is so incredulous.

He thinks they are Aliens drawing pictures in the clouds, lol

gbee

NO, they are definitely UFO traces caused by their high speed passing through the clouds.

Some have been observed after hearing a loud bang or rumble like thunder and the observer looked skyward to see cloud formations like this.

Maybe this post is better suited in the UFO Clouds are talking to us thread.

Funny someone already posted an almost duplicate reply in that thread too ... not looking at anyone. )

Lumi

Duiske wrote: »

This thread will shed a bit of light on why Demonspawn is so incredulous.

He thinks they are Aliens drawing pictures in the clouds, lol

Priceless!!! That's made my day - Cheers Duiske :D

ANDREWaim

I saw it at the time of coffee in the company where I work:



It was a cold day! Very different than we used in Brazil (08/05/2010 City:Guaxupé - Minas Gerais 9:00)!