Weird Cloud Explanation

Legs Akimbo

Grumblebum
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These 2 shots were seconds apart facing west and north west from Lane Cove in Sydney. There was a decent southerly - no whitecaps, so mebbe 10 knots. Whatever the windspeed it wasn't still. The north south runway was working, so planes were passing (mainly descending) but, at the distance from the airport of sub 15 km contrails are probably out of the question. So why? Theories?



[url=https://flic.kr/p/MouGmr]
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skifree

A disciple of the blessed avi giraffe
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The first one is vertical. The second are pretty much at right angles to the direction of flight. And if the first one only appears vertical because of perspective, it is also perpendicular to flight path.

I think the vertical is an illusion
 

piolet

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If it aint contrails <insert chemtrails joke here> my guess would for be air mass interaction, light breeze at sea level can easily have a raging SW'ster at 1000' and various others in short order after. (The SWster is a classic for the basin)
The different breezes would have differnt moisture/temp profiles leading to all sorts of things
 

Legs Akimbo

Grumblebum
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If it aint contrails <insert chemtrails joke here> my guess would for be air mass interaction, light breeze at sea level can easily have a raging SW'ster at 1000' and various others in short order after. (The SWster is a classic for the basin)
The different breezes would have differnt moisture/temp profiles leading to all sorts of things
It was a south wester.
 

skifree

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Contrails can form long after the aeroplane has passed.
 

skifree

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If it aint contrails <insert chemtrails joke here> my guess would for be air mass interaction, light breeze at sea level can easily have a raging SW'ster at 1000' and various others in short order after. (The SWster is a classic for the basin)
The different breezes would have differnt moisture/temp profiles leading to all sorts of things

I'd agree possible, but it does not look like any of the huge variety of air mass interactions I'm aware of.
 

piolet

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I'd agree possible, but it does not look like any of the huge variety of air mass interactions I'm aware of.
Whilst it can be massive, it can subtle too? Im just trying to say that as you go up (or down) through the levels, even, say, only below 5000' above the deck the air mass is frequently not homogeneous.
 

Snow Blowey

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I was in a paddock near Dubbo all day and saw all those contrails being formed before they blew over Sydney.

Strong westerly flow up high. Day started with the "its going to get nasty in 24hours" high cloud but they all cleared to a nice sky with nothing but con trails.
 

Legs Akimbo

Grumblebum
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I was in a paddock near Dubbo all day and saw all those contrails being formed before they blew over Sydney.

Strong westerly flow up high. Day started with the "its going to get nasty in 24hours" high cloud but they all cleared to a nice sky with nothing but con trails.
Do contrails stay intact over that distance? I'm amazed.
 

skifree

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So Sydney is the centre of the universe.

Contrails like a lot of clouds are subject to movement by the winds as noted by @Snow Blowey

And there are some shitfully strange flight routes.

I'm been in deep South West Tas and watched a flight head due South and keep going on more than one trip. Still not sure where they were going. There is not a lot to fly to due South of Tas.
 

Snow Blowey

Old n' Crusty
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Dubbo is only 300km straight line from Sydney CBD.

If i head east in the morning i can see the Syd - Brisbane con trails about a few fingers up from the horizon. We get plenty of Melb-Brisbane and i think that what lots of todays trails were.

We also get lots of big 4 engine jobbies up high heading NW straight over the top. Guessing its Sydney - Singapore. And i'd say that was your vertical trail.

I've had a Sydney-Gold Coast flight where it was nice and clear and i could see the Warrumbungles in the far distance.
 
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Drewboy

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That's the Qantas Sydney to Johannesburg flight.Get the plane finder app and you know what's going overhead.
So Sydney is the centre of the universe.

Contrails like a lot of clouds are subject to movement by the winds as noted by @Snow Blowey

And there are some shitfully strange flight routes.

I'm been in deep South West Tas and watched a flight head due South and keep going on more than one trip. Still not sure where they were going. There is not a lot to fly to due South of Tas.
 

Drewboy

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And the first photo if that contrail was north to south and overhead that would be a Brisbane to Hobart or Launceston and the second photo if that's looking west and the contrails are going south to north that's Melbourne to Brisbane or Gold Coast.
 

Legs Akimbo

Grumblebum
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First is looking west, so if the verticality is an illusion the contrail would be east - west.

The second is looking north west, so the contrails would be north east - south west.

All probably.
 

Drewboy

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Ok the first would be Aukland or Christchurch to Singapore or KL etc and the second one would be Bris or Gold Coast to Melbourne
 

Drewboy

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Not at all depanding on upper level winds Sydney is under the NZ to Singerpore and KL flight path and sometimes Aukland to Adl and Perth,get the Plane Finder app and you see what's flying overhead.The Singapore WSSS-NZAA flew over Sydney this morning and the return is now over the Tasman on a more northern route.SQ286 NZAA-WSSS.
 
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POW Hungry

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As pointed out, it's definitely a contrail. Contrary to belief there are aircraft flying at 30,000ft above many capital cities as they actually have the least traffic at that altitude. Sydney is a midway point for countless flight paths...
 

skifree

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Anything to do with this?

This thing is a very very local effect. There are few places about the world where these weather events occur, many regular as clockwork. There is reliable lift to be found and you can fly a glider a long the full length of the cloud. A few people over the years have tried to set long distance soaring records using the effect.

MorningGloryCloudBurketownFromPlane.jpg
 

walrusballs

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I saw these!! my wife said what is that!! I told her its clouds!!! 100% contrails.. in line with the high flight path(rather than the low level one) over my house. Reminds me of a situation a few years ago when people started calling Nova FM reporting a crazy alien cloud over towards the mountains which turned out to be contrails again almost in the same location of these ones.... Speaking of aliens. What if aliens are much smaller than us(like 2 inches tall), and are already here....
 

spottedreptile

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Why this obsession with great circle routes? It may be the shortest distance in the air but not necessarily in time - a lot of factors combine to make a flight plan, wind, jetstream, overfly rights and charges, political situations etc. None of the last are applicable here really, but weather certainly is.
Looks very like a contrail going over the top. Wind at the surface isn't necessarily wind up at 40,000 feet either, they may be going totally different ways.
 
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skifree

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Why this obsession with great circle routes? It may be the shortest distance in the air but not necessarily in time - a lot of factors combine to make a flight plan, wind, jetstream, overfly rights and charges, political situations etc. None of the last are applicable here really, but weather certainly is.
Looks very like a contrail going over the top. Wind at the surface isn't necessarily wind up at 40,000 feet either, they may be going totally different ways.

Airspace arrangements are usually the governing factor with pilots then requesting different flights levels and so on if they see a weather issue to avoid or take advantage of. Am I on the right track here @dibl0c or @piolet
 
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Legs Akimbo

Grumblebum
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Why this obsession with great circle routes? It may be the shortest distance in the air but not necessarily in time - a lot of factors combine to make a flight plan, wind, jetstream, overfly rights and charges, political situations etc. None of the last are applicable here really, but weather certainly is.
Looks very like a contrail going over the top. Wind at the surface isn't necessarily wind up at 40,000 feet either, they may be going totally different ways.
Because my assumption is that great circles are the starting point and everything else is a deviation.
 

piolet

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Because my assumption is that great circles are the starting point and everything else is a deviation.
Essentially yes with emphasis on organisation for shorter routes. Longer independent routes will just be GC with wind adjustment. Both interact often so yes and no.
Political is interesting eg. Sydney to northern china; no flyover Taiwan nor formosa strait; adds maybe 45 mins going around - north almost over hkg, south you actually go thru sth korean airspace and southern japan (home island group). Also Iraq/itan etc
Check the routes el al take through their backyard...
@NeoSamurai would posess greater knowledge for the organisation
 
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Ultra

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I'm been in deep South West Tas and watched a flight head due South and keep going on more than one trip. Still not sure where they were going. There is not a lot to fly to due South of Tas.

Syd to anywhere in South America goes pretty much due south over Antartica. great way to see it, just book a return flight to South America.
 

skifree

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Syd to anywhere in South America goes pretty much due south over Antartica. great way to see it, just book a return flight to South America.

Awesome, will have to think of a reason to go to South America.

Any idea of which flights are over Antartica during daylight?

:doh:

Just figured it would be any during the Antartic Summer.
 
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dibl0c

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This thing is a very very local effect. There are few places about the world where these weather events occur, many regular as clockwork. There is reliable lift to be found and you can fly a glider a long the full length of the cloud. A few people over the years have tried to set long distance soaring records using the effect.

MorningGloryCloudBurketownFromPlane.jpg

Was lucky enough to see this for myself when working up in the gulf. Not as well formed though.

Q4eNP0n.jpg
 
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