Chemtrails

[dragartist]

I know it must be a slow news day, apart from RAF jets chasing bears over the Black Sea.
This took my eye
https://www.bbc.co.uk/news/uk-england-oxfordshire-45296731

I have seen a few pictures of interesting cloud formations but never anything like this. Even a thread running on our local around town Facebook page.

My most memorable Association with clouds was having taken off from Wyton through low cloud into bright sunshine, perfect silhouette of the Nimrod on top of the cloud as we banked over St Ives. A bit like the famous photo of the C130 [very] low level over the desert. I wish I had had my camera but understandably they were forbidden in those days. (May have got tangled up in the sidestick!)

[Melchett01]

They are definitely eye catching aren’t they? But I do hope they weren’t chemtrails! Then again the conspiracy theory videos on You tube over alleged chemtrail activity are amusing to watch. After all, why believe in physics when a tinfoil hat conspiracy theory will do!

I believe there is an inverse effect to contrails called distrails but I have rarely heard of or seen. Langley might be able to shed light.

[Rhino power]

https://cimg6.ibsrv.net/gimg/www.gmforum.com-vbulletin/350x350/were_all_doomed_25d2f80c974af1a038e69f909e5e36475d3cf0f6.jpg
-RP

[langleybaston]

They are definitely eye catching aren’t they? But I do hope they weren’t chemtrails! Then again the conspiracy theory videos on You tube over alleged chemtrail activity are amusing to watch. After all, why believe in physics when a tinfoil hat conspiracy theory will do!

I believe there is an inverse effect to contrails called distrails but I have rarely heard of or seen. Langley might be able to shed light.

seeing as how .........
distrails are much much rarer than contrails and "in my time" nobody understood them. Because they seemed not to matter to the customer [the RAF] we did little or no research. All I will say is that every time I got excited by what I thought was a distrail it turned out to be the shadow of a high contrail on a thin lower cloud layer.

The famous green flash did have the grace to flash once, but that is another story.

[Fitter2]

The third photographs in the BBC link looks much more like wave clouds; it would be interesting to know the wind direction. Cloud streets are oriented up/downwind; wave clouds crosswind.

[langleybaston]

The third photographs in the BBC link looks much more like wave clouds; it would be interesting to know the wind direction. Cloud streets are oriented up/downwind; wave clouds crosswind.Possibly, but, if so, a very very short wavelength.

[treadigraph]

I always thought cloud streets were lines of individual developing cumulus moving downwind from particularly strong thermal generators? Those almost look like roll clouds! Last one looks like lenticular to me too - I have once or twice seen similar clouds in the lee of the north and south downs when there has been a fairly strong southerly wind blowing.

[India Four Two]

Those don’t look like cloud streets to me.

I saw some similar but lower level clouds in May this year, south of Calgary. The location is about 50 miles downwind of the Rockies, so we quite often see wave clouds, but they are oriented roughly north-south.

The clouds I saw were much lower level than normal wave clouds and were oriented east-west. I estimated the cloud bases were about 4000’ AGL.

Looking North:
https://cimg4.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x1504/4c321752_ea54_411d_9176_3c8731bffc82_1a970f69ffb8a760be9eaf2 e595b7941122a71f4.jpeg
Looking East:
https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x1504/42260271_7888_419d_8d67_0714f5f8bbf5_7533f4baf585ac3b77fa9b9 2e99e4cda9b980464.jpeg

[blind pew]

Wave type cloud streets can be formed by wind shear when an upper layer has a marked change of direction and increase of speed. It's possible to soar the windward side of the street.
The thermals are suppressed in the blue bit and channelled to form the Cu/ wave cloud.

[dragartist]

My hopes that this would generate into an educational topic have been met, thank you.
I remember a glider pilot telling me about waves off the mountains when gliding in Chilie almost carrying him to Argentina.
no huge mountain range across Great Britain to bring about this phenomenon.

[langleybaston]

Fairly common to lee of Pennines: RAF Leeming and the infamous "gap wind" which the customers understood better than the resident Met men, me included.
"Mind the Gap!" indeed.

[Pontius Navigator]

LB,see Cloud Guru on Jet Blast.

[langleybaston]

LB,see Cloud Guru on Jet Blast.

Thank you, will do.

[India Four Two]

Fairly common to lee of Pennines

Fairly common downwind of Snowdonia too. I vividly remember an instrument trip in a Chipmunk, west of Shawbury. I was under the hood, trying to climb. I had full power, the correct attitude and airspeed, flaps were up, the air was smooth as silk and we were going down at 200' per minute. I had no clue what was going on. My CFI was laughing his socks off! We were in a down-going wave.

[gearlever]

Spraying nighttime only