What kind of cloud is this pale band from left to right?

It did not disperse or significantly move over a ten minute period. It’s way to wide and stable to be a contrail.

dv said:

What kind of cloud is this pale band from left to right?

It did not disperse or significantly move over a ten minute period. It’s way to wide and stable to be a contrail.

Where are you?

You are either under a jet-stream or it is a roll cloud(but looks too high).

Postpocelipse said:

You are either under a jet-stream or it is a roll cloud(but looks too high).

more like a weak cold front.

roughbarked said:

dv said:

What kind of cloud is this pale band from left to right?

It did not disperse or significantly move over a ten minute period. It’s way to wide and stable to be a contrail.

Where are you?

This picture was taken in Perth. The camera is facing southward. This band is about 22 degrees above the horizon, perhaps 3 degrees thick. Taken today, at about 3:40 pm.

Were the puffy bits with it or just near it?

roughbarked said:

Postpocelipse said:

You are either under a jet-stream or it is a roll cloud(but looks too high).

more like a weak cold front.

I was also trying to think of that description without enough info. Cheers.

kii said:

Were the puffy bits with it or just near it?

Um … what’s the difference?

https://cloudappreciationsociety.org/

They also have a faceborked page. They might be of some help or it might just be a bunch of people who like to find animal shapes in clouds.

dv said:

kii said:

Were the puffy bits with it or just near it?

Um … what’s the difference?

With it aka as with it.
Near it aka sort of in the same area, but not.

Also did the puffy clouds move, was there wind and are you friends with Steve on fb?

kii said:

dv said:

kii said:

Were the puffy bits with it or just near it?

Um … what’s the difference?

With it aka as with it.
Near it aka sort of in the same area, but not.

Also did the puffy clouds move, was there wind and are you friends with Steve on fb?

The puffy clouds, which as you can see were nearer to me than the band was, did move and change a bit, which I suppose indicates that the band was at some high altitude.

“With it aka as with it.
Near it aka sort of in the same area, but not.”

No idea what that means. They were … adjacent to it.

dv said:

roughbarked said:

dv said:

What kind of cloud is this pale band from left to right?

!http://dazvoz.com/cloud0160229_153940-1-scale.jpg

It did not disperse or significantly move over a ten minute period. It’s way to wide and stable to be a contrail.

Where are you?

This picture was taken in Perth. The camera is facing southward. This band is about 22 degrees above the horizon, perhaps 3 degrees thick. Taken today, at about 3:40 pm.

Which all says it isn’t a morning glory.

I see these weal cold fronts often.

weal weak.

Anyone else see advertisements on this page?
http://www.bom.gov.au/australia/index.shtml

No ads for me.

dv said:

Anyone else see advertisements on this page?
http://www.bom.gov.au/australia/index.shtml

I don’t see advertisements anywhere.

kii said:

No ads for me.

They are there though.

dv said:

Anyone else see advertisements on this page?
http://www.bom.gov.au/australia/index.shtml

roughbarked said:

kii said:

No ads for me.

They are there though.

The question was does anyone see the ads. I don’t see any ads.

kii said:

roughbarked said:

kii said:

No ads for me.

They are there though.

The question was does anyone see the ads. I don’t see any ads.

Neither do I.

Anyway,

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

mollwollfumble said:

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

I’m tempted to say that their life span must surely be limited to a few billion years, but if I did dv would probably have a go at me for being pedantic, so I won’t.

I wonder what the half life is of contrail cloud, a good one.

mollwollfumble said:

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

Yes but that isn’t what it is.

The Rev Dodgson said:

mollwollfumble said:

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

I’m tempted to say that their life span must surely be limited to a few billion years, but if I did dv would probably have a go at me for being pedantic, so I won’t.

For individual isolated clouds, “forever” means from sunrise to sunset. Most contrails are quite distorted after 20 minutes, but not if the atmosphere at that height is “stably stratified” (which is defined in terms of temperature gradient), the air is close to saturation point and the wind speed is slow.

In London it’s common for contrails from multiple aircraft to grow and merge until 40% of the whole sky is covered by ex-contrails.

mollwollfumble said:

The Rev Dodgson said:

mollwollfumble said:

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

I’m tempted to say that their life span must surely be limited to a few billion years, but if I did dv would probably have a go at me for being pedantic, so I won’t.

For individual isolated clouds, “forever” means from sunrise to sunset. Most contrails are quite distorted after 20 minutes, but not if the atmosphere at that height is “stably stratified” (which is defined in terms of temperature gradient), the air is close to saturation point and the wind speed is slow.

In London it’s common for contrails from multiple aircraft to grow and merge until 40% of the whole sky is covered by ex-contrails.

Something I noticed in Perth was we very rarely got jet contrails chemtrails but they are more common in the last couple of years (still fairly uncommon though)

mollwollfumble said:

> It’s way to wide and stable to be a contrail.

No it’s not. It’s well known, from for example London, that under the correct atmospheric conditions of wind and humidity contrails can widen and stabilize so as to last essentially forever.

What?

No.

mollwollfumble said:

In London it’s common for contrails from multiple aircraft to grow and merge until 40% of the whole sky is covered by ex-contrails.

I must say that, having lived a few miles from Heathrow in my teens and early 20’s, I was surprised to read that chemtrails are a recent innovation.

The UK government has been pumping them out for at least 50 years.

It looks like a form of cumulus, probably quite close to the coast. I’d also suggest that it was mid afternoon, possibly a little later, that the day had been warm to hot, and that there was now a seabreeze. Here’s how they form: the land is warmer that the nearby ocean, and this warms the air in contact with it. The warmer air rises, leaving a lower pressure region in its place, so the air over the sea moves in to take its place (this is a standard sea breeze scenario). The air moving in from the sea also warms up, and also rises, but since it came from over the water it has water vapour dissolved in it, which condenses out into cloud as the air rises. Since this happens along a stretch of coast, the band of cloud formed follows the shape of the coast, appearing as a long band, as seen in the photo. Cloud thus formed generally lasts about 20-30 minutes, and frequently has small puffy clouds around it, also as seen in the photo.

The Rev Dodgson said:

mollwollfumble said:

In London it’s common for contrails from multiple aircraft to grow and merge until 40% of the whole sky is covered by ex-contrails.

I must say that, having lived a few miles from Heathrow in my teens and early 20’s, I was surprised to read that chemtrails are a recent innovation.

The UK government has been pumping them out for at least 50 years.

And I grew up in Melbourne, near a flight path, not exactly under it. I also was surprised that people thought things I considered a normal consequence of planes going over were in some way sinister. I guess my Mum was right. The Pug (her Pug) in the backyard kept the planes from landing there. The evidence? No plane ever landed in the backyard at Box Hill North.

something i just learned. in the tv show Young Dracula the main vampire’s factotum is named Renfield. Renfield was the factotum of Bram Stoker’s Dracula.

/* chemtrails are a recent innovation */

rainbows too, I remember

Wocky said:

It looks like a form of cumulus, probably quite close to the coast. I’d also suggest that it was mid afternoon, possibly a little later, that the day had been warm to hot, and that there was now a seabreeze. Here’s how they form: the land is warmer that the nearby ocean, and this warms the air in contact with it. The warmer air rises, leaving a lower pressure region in its place, so the air over the sea moves in to take its place (this is a standard sea breeze scenario). The air moving in from the sea also warms up, and also rises, but since it came from over the water it has water vapour dissolved in it, which condenses out into cloud as the air rises. Since this happens along a stretch of coast, the band of cloud formed follows the shape of the coast, appearing as a long band, as seen in the photo. Cloud thus formed generally lasts about 20-30 minutes, and frequently has small puffy clouds around it, also as seen in the photo.

One thing I happen to know about sea breezes from the bad old days when I was a wind engineer, is that the height of maximum speed is remarkably close to the ground, only about 100 metres up. Given that cloudbase tends to be of the order of 1000 metres up, you seldom see clouds associated with sea breezes. There are exceptions, but I’ve never seen one live. The Gulf of Carpentaria is said to be the only location in the world in which clouds associated with sea breezes occur on a regular basis.

buffy said:

And I grew up in Melbourne, near a flight path, not exactly under it. I also was surprised that people thought things I considered a normal consequence of planes going over were in some way sinister. I guess my Mum was right. The Pug (her Pug) in the backyard kept the planes from landing there. The evidence? No plane ever landed in the backyard at Box Hill North.

That must be it. We’re in Melbourne near a flight path and not exactly under it. We don’t have a Pug to keep the planes from landing here, so that must be why a light plane landed hard on the garage of my next door neighbour.

mollwollfumble said:

One thing I happen to know about sea breezes from the bad old days when I was a wind engineer, is that the height of maximum speed is remarkably close to the ground, only about 100 metres up. Given that cloudbase tends to be of the order of 1000 metres up,

Cloudbase can vary considerably, from ground level (fog) to 100000 feet or more (cumulonimbus and cirrus). Cloud at different levels is commonly reported on pilots’ weather reports, and is frequently seen at 1000 feet (vertical distances in aviation are reported in feet, though horizontal distances are in either metres or nautical miles.)

mollwollfumble said:

you seldom see clouds associated with sea breezes. There are exceptions, but I’ve never seen one live. The Gulf of Carpentaria is said to be the only location in the world in which clouds associated with sea breezes occur on a regular basis.

This is totally inconsistent with my experience. I’ve seen cloud from seabreezes quite frequently, even (and particularly) over Port Phillip Bay (eg cloud following the coast from Geelong to Queenscliff.)

> Cloudbase can vary considerably

Don’t I know it! one of my major successes at CSIRO was to develop and algorithm for calculating the cloudbase from latitude and ground level temperature and humidity. It’s not something you can find in a book.

TD: Where are we going? Cloudbase?
KATE: You mean the Valiant?
OSGOOD: Cloudbase was Thunderbirds.

dv – did you see the photos of the similar cloud further south of you? On the fb page for the people who appreciate clouds.

kii said:

dv – did you see the photos of the similar cloud further south of you? On the fb page for the people who appreciate clouds.

yes

dv said:

kii said:

dv – did you see the photos of the similar cloud further south of you? On the fb page for the people who appreciate clouds.

yes

good

Johnny Cash – Give My Love To Rose

Thomo said:

Johnny Cash – Give My Love To Rose

um