What are these stationary clouds? [Lee clouds]

Stephanie

New Member
I took this picture in the mountains of NC a few weeks ago. This cloud stayed over the sun for at least 4 hours. It was very windy that day and other clouds were drifting. 485549_631307486879544_920240466_n.jpg
Curious as to why this stayed there for so long? It basically was like that all day but not as pronounced as the day went on.
 

Mick West

Administrator
Staff member
I took this picture in the mountains of NC a few weeks ago. This cloud stayed over the sun for at least 4 hours. It was very windy that day and other clouds were drifting. 485549_631307486879544_920240466_n.jpg
Curious as to why this stayed there for so long? It basically was like that all day but not as pronounced as the day went on.

The lower part looks like a lenticular cloud. They essentially constantly re-form in the same spot.

Here's an example, note everything is blown left to right, but the cloud never changes position:



Most of the picture though seems like high level clouds, and the wind is simply very different at high altitudes.

Here's another from NC that looks more like yours:

 

solrey

Senior Member.
I see "stationary" clouds rather frequently where I live on the eastern side of the Oregon Coast Range and they're even more prominent east of the Cascades. I would simply identify them as lee/gravity wave clouds in general, of which lenticulars are one of the cloud types.

http://selair.selkirk.bc.ca/trainin...ding_Lenticular_Clouds_and_Mountain_Waves.pdf

http://www.atmos.washington.edu/2010Q1/536/2003AP_lee_waves.pdf

Here are some time-lapse vids of lee/gravity wave clouds.

http://www.youtube.com/watch?v=O_Gssj6Sp-A

http://www.youtube.com/watch?v=KePl-pnz6Pk

http://www.youtube.com/watch?v=Dvl3PrXwBkI

http://www.youtube.com/watch?v=sa3lzdt5DmQ

http://www.youtube.com/watch?v=qumdahPp8Qo

cheers
 

M Bornong

Senior Member.
I shot this a few years ago, in the southeastern Sierras. The time span is approx. 4 hrs.


These are a few stills of lenticular clouds I've shot in the same area, over the years.
031.jpg032.jpg033.jpg040.jpgDSCF4036.JPGDSCF4044.JPG
 

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cloudspotter

Senior Member.
I saw an excellent demonstration of the motion within lenticular clouds this morning but unfortunately was in no position to take photos. I spotted a lenticular type cloud with what appeared to be a distrail running through it. The distrail moved relatively quickly across the cloud from west to east until it disappeared off the edge of it. Fascinating to watch. Gutted I couldn't get photos.
 

Mick West

Administrator
Staff member
I saw an excellent demonstration of the motion within lenticular clouds this morning but unfortunately was in no position to take photos. I spotted a lenticular type cloud with what appeared to be a distrail running through it. The distrail moved relatively quickly across the cloud from west to east until it disappeared off the edge of it. Fascinating to watch. Gutted I couldn't get photos.

I know how you feel. I constantly see cool clouds and trails and wish I had my big camera. I think one of the attractions of these phenomena is that they are transitory, and often quite unique.

Round here the sky is always moving pretty fast, so if I see a contrail across the moon, or a nice edge shadow, I know it will be gone in a minute.
 

pseacraft

Active Member
That is why I nearly always keep my camera in the car, you never know when you see something that deserves pulling over. I've have caught many an interesting subject and kick my self in the boot when I accidentally leave it at home like this morning when I had a chance for a baby Blunt-Nosed Viper out in the open in a heavily Falcon patrolled area. Could have been interesting...
 

cloudspotter

Senior Member.
I know how you feel. I constantly see cool clouds and trails and wish I had my big camera. I think one of the attractions of these phenomena is that they are transitory, and often quite unique.

Round here the sky is always moving pretty fast, so if I see a contrail across the moon, or a nice edge shadow, I know it will be gone in a minute.

A few months ago I was sitting with my other half on a bit of high land taking a breather on one of our walks and admiring the view. I pointed out a fractus cloud that had formed ahead of us and was already dissipating as it moved overhead. She mentioned something that hadn't occurred to me - as there weren't any people around we were very likely the only people to see that cloud and no one else ever would.
 

Mick West

Administrator
Staff member
A few months ago I was sitting with my other half on a bit of high land taking a breather on one of our walks and admiring the view. I pointed out a fractus cloud that had formed ahead of us and was already dissipating as it moved overhead. She mentioned something that hadn't occurred to me - as there weren't any people around we were very likely the only people to see that cloud and no one else ever would.

That reminds me of an idea I had. That little fractus would look very different viewed from the side. Cloud are very three dimensional, but we only get a 2D view of them. It would be very cool if somehow we could get 50 people arranged in a 20 mile radius circle, and have then all take a photo of a cloud simultaneously, capturing it in full 3D at one precise point in time. You could then make the sequence of images into an animation of the cloud spinning, viewed from every side.

Something like:
http://vimeo.com/videoschool/lesson/339/360-building-capture
 

cloudspotter

Senior Member.
That reminds me of an idea I had. That little fractus would look very different viewed from the side. Cloud are very three dimensional, but we only get a 2D view of them. It would be very cool if somehow we could get 50 people arranged in a 20 mile radius circle, and have then all take a photo of a cloud simultaneously, capturing it in full 3D at one precise point in time. You could then make the sequence of images into an animation of the cloud spinning, viewed from every side.

Something like:
http://vimeo.com/videoschool/lesson/339/360-building-capture
[video=vimeo;55832096]http://vimeo.com/55832096[/video]

Good luck co-ordinating that
OK we're going for that one everybody.
Which one?
The one that looks like a rabbit.
I only see an elephant.
I see a dragon.
 

Mick West

Administrator
Staff member
Good luck co-ordinating that
OK we're going for that one everybody.
Which one?
The one that looks like a rabbit.
I only see an elephant.
I see a dragon.

Yeah, so my next idea was to get people to install remote control HD web cams on top of their houses, with pan, tilt and zoom, you could have a real time 3D view of any cloud within the the circle.
 

cloudspotter

Senior Member.
Yeah, so my next idea was to get people to install remote control HD web cams on top of their houses, with pan, tilt and zoom, you could have a real time 3D view of any cloud within the the circle.

Some people have got way too much time on their hands ;)
 

Mick West

Administrator
Staff member
Some people have got way too much time on their hands ;)

Unfortunately not enough to do this :)

One thing you could do is just have two camera (a few miles apart), which you could use to triangulate contrails to measure altitude. The chemtrailers should give that a go.
 

cloudspotter

Senior Member.
Unfortunately not enough to do this :)

One thing you could do is just have two camera (a few miles apart), which you could use to triangulate contrails to measure altitude. The chemtrailers should give that a go.

Seems like it would be the Australians if any of them did.
 

blargo

Member
I took this picture in the mountains of NC a few weeks ago. This cloud stayed over the sun for at least 4 hours. It was very windy that day and other clouds were drifting.
Curious as to why this stayed there for so long? It basically was like that all day but not as pronounced as the day went on.

We see this a great deal on the Front Range of Colorado. Here is a great video that shows many of these types of clouds with time lapse.
http://www.youtube.com/watch?v=P84WoxbDXCg
 

Jazzy

Closed Account
We see this a great deal on the Front Range of Colorado. Here is a great video that shows many of these types of clouds with time lapse.
http://www.youtube.com/watch?v=P84WoxbDXCg
Thanks for that. It's possible to see:
The air must contain a lot of water vapor.
The air is less turbulent with increasing altitude.
Higher layers travel in different directions.

What interests me is how the ambient sunlight conditions within such clouds can trigger small convective clouds which burst upward out of them. There's a whole set of them in the top right of my photo.
 

Cairenn

Senior Member.
Some years ago, I was camping out with friends and we noticed some smoke in the distance (when it is dry in TX/OK/KN you pay attention). It seemed to be someone burning trash. What was interesting was the small cloud that developed above it. The cloud was short lived, but obviously connected to the smoke providing condensation particles.
 

cloudspotter

Senior Member.
Some years ago, I was camping out with friends and we noticed some smoke in the distance (when it is dry in TX/OK/KN you pay attention). It seemed to be someone burning trash. What was interesting was the small cloud that developed above it. The cloud was short lived, but obviously connected to the smoke providing condensation particles.

Pyrocumulus?
 

Mick West

Administrator
Staff member
Some years ago, I was camping out with friends and we noticed some smoke in the distance (when it is dry in TX/OK/KN you pay attention). It seemed to be someone burning trash. What was interesting was the small cloud that developed above it. The cloud was short lived, but obviously connected to the smoke providing condensation particles.

It's more the updraft that's creating the cloud than it is the smoke. The warm air rises, and it carries with it water from combustion (burning practically anything makes water) and from heated vegetation. Expands, cools, cloud. It's like a contrail for the earth.:)
 

Cairenn

Senior Member.
I hadn't thought about that. We did discuss why it formed. I still need to back and take a meteorology class. I kept trying but it was also either opposite something I had to take, or hours after I would have left campus (computer school at that time).
 

JFDee

Senior Member.
Indeed, lenticularis are signs of "waves" (hi, electrojet!) at or close to mountainous areas when the wind is strong and steady. These waves make glider climbing possible even in wintertime when the thermals are weak.

Regarding "pyrocumulus": that's a good one!

Here is a bigger specimen above a power plant; the steam originates from cooling water, not from combustion though. The plane is an LS 8.

neresheim.jpg
 
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