Photos of Clouds and Skies (That you took yourself)

M Bornong

Senior Member
A tangent arc at sunset. Photos were taken at 17:25 official sunset was 17:20 pacific time. Bakersfield California, 1/28/17.

DSCF1606.JPG DSCF1608.JPG
 

Leifer

Senior Member
My nephew took this photo.
He got a job at MSP airport. He fuels the planes.
(bending the rules here slightly)
levi_sunset.jpg
 

Trailblazer

Moderator
Staff member
Some regularly spaced ripples on the back edge of Storm Doris at Woolacombe in Devon. And some contrails and a paraglider for good measure.

IMG_0262.JPG
 

Mick West

Administrator
Staff member
Steam cloud
Cumulus mediocris homogenitus :)

https://www.wmocloudatlas.org/homogenitus.html
 

Graham2001

Active Member
Did some looking into the term you quoted Mike and it looks like it, along with Contrails has just been added to the Cloud Atlas in the last few months, one thing that I always think of when seeing images like the one above and also the one used in the Cloud Atlas, is all the times that TV media when talking of industrial pollution use shots of cooling towers billowing steam into the air as a visual shorthand for 'nasty chemicals'. I think these new clouds are going to have a bit of a perception issue.
 
Last edited:

Mick West

Administrator
Staff member
Did some looking into the term you quoted Mike and it looks like it, along with Contrails has just been added to the Cloud Atlas in the last few months, one thing that I always thing of when seeing images like the one above and also the one used in the Cloud Atlas, is all the times that TV media when talking of industrial pollution use shots of cooling towers billowing steam into the air as a visual shorthand for 'nasty chemicals'. I think these new clouds are going to have a bit of a perception issue.
See discussion here:
There Are No New Clouds, Just New Latin Classifications

- Mick
 

Trailblazer

Moderator
Staff member
Nice example of how clouds can look drastically different in colour depending on the lighting. Photo taken heading east with the evening sun low behind (and to the left of) the car. Even small fluffy cumulus clouds look almost black while the more distant ones are bright white.

IMG_2096.JPG
 
Last edited:

Mick West

Administrator
Staff member
Even small fluffy cumulus clouds look almost black while the more distant ones are bright white.
It's one of this things that you simply don't notice and yet happens quite often. A few days ago someone asked me about a "odd small black cloud", pointing it out in the sky. It was just a cloud like this - low cloud shadowed by some distant cloud bank.
 

Trailblazer

Moderator
Staff member
It's one of this things that you simply don't notice and yet happens quite often. A few days ago someone asked me about a "odd small black cloud", pointing it out in the sky. It was just a cloud like this - low cloud shadowed by some distant cloud bank.
Yes this one was on a day with lots of towering convective clouds, heavy downpours interspersed with sunshine. Made for some good cloudscapes, but the contrast in colours here caught my attention.
 

Marin B

Active Member
Cumulus mediocris homogenitus :)
I'm not sure if this is another Cumulus mediocris homogenitus, or a natural cloud that is coincidentally near the same refinery as the cloud in my last post. This time the vantage point is in the hills east of the cloud (the earlier cloud was taken about the same distance away west of the cloud. As I got closer to the cloud, the shadow was actually about a quarter mile SW of the refinery, and I couldn't see any steam rising from the refinery. So maybe just a coincidence that the only cumulus for miles around just happened to be close to the refinery?

Chevron Cloud.JPG
 

Leifer

Senior Member
1495768017496820428225.jpg 14957677220841108938981.jpg Square/rectangular cloud.
Nearly straight edges.
Over LAX airport, today, 8pm.
 
Last edited:

MikeC

Closed Account
A couple of sunset chemtrails over the western hills of Lower Hutt, Wellington..... they were better 10 minutes earlier, but I couldn't stop!

20170621_171551[1].jpg
 

Trailblazer

Moderator
Staff member
This was the flight that left the distrail. It had only just taken off from Heathrow on the way to Madrid:

upload_2017-7-10_8-49-19.png

Although the altitude says 4,700ft there that is quite delayed. The tracklog on Flightaware shows that at the time it created the distrail (about 15:58:30) it was at about 3,200m (10,500ft).

upload_2017-7-10_8-52-37.png
 

SR1419

Senior Member
I'll try not to spam the board with too many MT pics but the sky is constantly changing here. So much to see compared to tranquil CA.

Some bubbly mammatus:

IMG_2851.JPG

and a "dry" thunderstorm. No rain reached the ground...at least where I was.

IMG_2860.JPG
 

Trailspotter

Senior Member
I have come to the conclusion by intuition, and observation, that these occur when RHi of the surrounding air is just below 100%, and the 'core' of the contrail is just above. The plane also needs to be a 'big bugger'.
Not exactly correct. Medium-sized planes, like E170 can produce these squiggly trails too:
Source: https://youtu.be/cqd6sJnQWN4

It all boils to the RHi of the mixture of exhaust and surrounding air at the distance behind the plane, where it got entrained into the wake vortices. The vortex-entrained trails became "insulated" from further mixing and last longer than non-entrained parts. If RHi of the entrained mixture is above 100%, the vortex-entrained trails will eventually end up by the Crow instability mechanism, otherwise they would dissipate before the vortices break up.

Edit:
Let's rephrase this: the squiggly trails are visualisation of the wake vortices and their interactions. The wake vortices are always present behind the plane, the trails just make them visible. For how long they are visible depends on RHi of the entrained mixture of exhaust and ambient air. If it is above 100%, the vortices (and trails) will last till they are broken by the Crow instability. If it is close but below 100%, that is the mixture reached the saturation point, but then was diluted before it was entrained in the vortices, the trails probably will last enough to get squiggly but will dissipate before the vortices break up.
 
Last edited:
Not exactly correct. Medium-sized planes, like E170 can produce these squiggly trails too:
Source: https://youtu.be/cqd6sJnQWN4

It all boils to the RHi of the mixture of exhaust and surrounding air at the distance behind the plane, where it got entrained into the wake vortices. The vortex-entrained trails became "insulated" from further mixing and last longer than non-entrained parts. If RHi of the entrained mixture is above 100%, the vortex-entrained trails will eventually end up by the Crow instability mechanism, otherwise they would dissipate before they the vortices break up.
If the surround air is supersaturated too much latent heat is released which breaks up the trail, I think.
 

Trailspotter

Senior Member
If the surround air is supersaturated too much latent heat is released which breaks up the trail, I think.
If the surround air is supersaturated too much the resulting contrail will envelope the wake vortices. There still will be more dense trails inside them, which eventually will break up (by the Crow instability) with the formation of contrail pendules.
 

SR1419

Senior Member
89746A44-7C6D-4BE0-9A6E-D7FB15B8332D.jpeg Back in Cali for the Holiday...took a post Thanksgiving jaunt to Fallen Leaf Lake (Tahoe area) and noticed this irridesence (i dont think its a sun dog but maybe?)
 

Hevach

Senior Member
Didn't realize it was supermoon time again, I didn't see one silly article leading up to it this year. Has that one fallen out of vogue?
 
Top