Persistent contrails and overcast the day after

WavedRhyme

New Member
Why is it everytime on a day where there is a clear sky and i see lots of persistent contrails the next day it is always so cloudy you cant see any sky at all?
 

Pete Tar

Senior Member.
The fact that the contrails persist means there is a front moving in, pushing the air that is right for persistent contrails ahead of it.
It seems as if the contrails 'cause' the high overcast clouds, but really they just indicate the presence of saturated air that precedes the cirro-stratus that follows. The contrails themselves are just man-made cirro-stratus.
(that is my basic amateur understanding anyway)
 

HappyMonday

Moderator
Why is it everytime on a day where there is a clear sky and i see lots of persistent contrails the next day it is always so cloudy you cant see any sky at all?

...because you're linking two things which happen in the sky above you without understanding of the mechanics that govern the behaviour of that environment. Are you sure it's 'always' cloudy, without fail, really?

People who made a link between a recent vaccination of their children and the onset of symptoms of autism made a similar leap.

There are better people here than me to explain any connection which may exist between humidity and super-saturation of ice above 30k feet (which is the reason you see expanding, persistent contrails) and the following days weather patterns, but suffice to say you'll find it's the overall conditions in the atmosphere and not the presence of the contrails themselves that are at fault, if anything.

Planes are not spraying to change the weather over your town.
 

CbIncus

Member
WavedRhyme, the things you've described are connected with major weather systems like a warm or occlusion front, or an upper-level disturbance. Vast areas of cirrus clouds are created by these systems, and the clouds (it means ice-supersaturated regions too) are at the leading edge of them. High cirrus are usually followed by thick altostratus (the sun can't be visible) or nimbostratus, which bring precipitation.
 

Cairenn

Senior Member.
Recently I was driving around Dallas one afternoon. When I left my house, I noticed a couple of persistent contrails. An hour or so later, I noticed a cirrus bank moving in. Within a 2-3 hours, that cirrus layer was overhead. Someone that had been inside during those hours could have easily assumed that the contrails spread to cover the entire sky.
 

Mick West

Administrator
Staff member

George B

Extinct but not forgotten Staff Member
I still has an explanation though. A plane flying though a region ice supersaturated air. Just that in this case it was the only plane, and it flew in circles, so made an unusually dense and singular contrail.
However, this was on a weekend day if I remember correctly and there were many other aircraft over the UK . . . this one seemed to initiate a cascade of cirrus while the others did not seem too. . . . this effect has been witnessed before. . . and is not easily explained .. . .
 

Mick West

Administrator
Staff member
However, this was on a weekend day if I remember correctly and there were many other aircraft over the UK . . . this one seemed to initiate a cascade of cirrus while the others did not seem too. . . . this effect has been witnessed before. . . and is not easily explained .. . .

Not true. There were several other contrails from normal planes in that area. The was simply the most distinct and most concentrated one. The other contrails also contributed to the cirrus.



You can see the contrails outside the spiral area grow here:

 
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George B

Extinct but not forgotten Staff Member
Not true. There were several other contrails from normal planes in that area. The was simply the most distinct and most concentrated one. The other contrails also contributed to the cirrus.



You can see the contrails outside the spiral area grow here:
I am not really disagreeing with you . . . what I am trying to say is that sometimes in the clear sky . . . where there appears to be no indication that cirrus clouds would form they sometimes bloom and the bloom can appear to be initiated by a single or a few events such as a persistent contrail . . . predicting such cascading events is not easily predicted . . .
At flight altitudes, conditions that can support contrail-generated cirrus clouds exist 10%–20% of the time in clear air and within existing cirrus (Gierens et al. 1999; Jensen et al. 2001). Additionally, cirrus may form at lower supersaturations on aerosols derived from jet aircraft than on aerosols from natural sources (Jensen and Toon 1994). Therefore, high-altitude air traffic has the potential for increasing cirrus coverage and thickening existing cirrus clouds by generating additional ice crystals. If other relevant variables are steady over time, then cirrus coverage should increase where air traffic is significant. http://journals.ametsoc.org/doi/full/10.1175/1520-0442(2004)017<1671:CCTAC>2.0.CO;2
Content from External Source
 

Mick West

Administrator
Staff member
I am not really disagreeing with you . . . what I am trying to say is that sometimes in the clear sky . . . where there appears to be no indication that cirrus clouds would form they sometimes bloom and the bloom can appear to be initiated by a single or a few events such as a persistent contrail . . . predicting such cascading events is not easily predicted . . .
At flight altitudes, conditions that can support contrail-generated cirrus clouds exist 10%–20% of the time in clear air and within existing cirrus (Gierens et al. 1999; Jensen et al. 2001). Additionally, cirrus may form at lower supersaturations on aerosols derived from jet aircraft than on aerosols from natural sources (Jensen and Toon 1994). Therefore, high-altitude air traffic has the potential for increasing cirrus coverage and thickening existing cirrus clouds by generating additional ice crystals. If other relevant variables are steady over time, then cirrus coverage should increase where air traffic is significant. http://journals.ametsoc.org/doi/full/10.1175/1520-0442(2004)017<1671:CCTAC>2.0.CO;2
Content from External Source

There are very specific and well understood reasons for that though. The difficulty is in measuring regions of ice supersaturation.

Contrails can form in clear blue skies where cirrus clouds will not form, because they add water, temporarily raising humidity.

The resultant cirrus will persist because cloud persistence occurs at a lower relative humidity than cloud creation.
 

George B

Extinct but not forgotten Staff Member
There are very specific and well understood reasons for that though. The difficulty is in measuring regions of ice supersaturation.

Contrails can form in clear blue skies where cirrus clouds will not form, because they add water, temporarily raising humidity.

The resultant cirrus will persist because cloud persistence occurs at a lower relative humidity than cloud creation.
Yes, I agree . . . the key is what pushes the occasional contrail into a bloom of cirrus and cirrus haze and when does it not . . . simply the amount of Ice supersaturated air . . . if so can we determine when this will happen via atmospheric soundings or not? I think this is an issue beyond just simple inquiry I think it has implications on how to mitigate climatic impact and explaining to chemtrail conspiracy advocates what is really going on . . .
 
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