con trail forecast (ice, average, 2014, days)

[saltine]

if atmosperic conditions determine weather contrails linger or disperse we should be able to get con trail forecasts... guess thats what they mean when they say filtered sunshine. I miss blue skies.

[Weidehond]

Where do you live? At my location there are contrails too, but also many days pass by without. It is very difficult to predict when contrails do occur. I think they mostly appear in high pressure situations....but not always.

[Walshie79]

They are a menace in Britain, forming large areas of imitation cirrus/cirrostratus cloud that can dim the sun for hours at a time. We get few enough clear days as it is and it is maddening to see one ruined by this pollution that nobody seems willing to combat (while things at ground level are subject to all sorts of petty rules and regulations).

Until the late 90s the only contrails we saw here were the thin lines behind planes that lasted minutes. You still get them, but just as often it's this new kind that form thick marks, that can spread out into what can be easily taken for cloud. It really has only appeared since about 1998, and it seemed to get much more common from about 2004. Either the composition of the air up there has changed or what's in the aircraft exhaust has. And someone needs to sort it out.

[Rozenn]

Contrails form when the relative humidity with respect to ice around where the plane flies is 100%. On average, it corresponds to a relative humidity of 70%, but it will vary depending on the weather conditions at the upper levels. Your best bet would be to check the 300 hPa level relative humidity forecasts. The 300 hPa level is close to where most planes fly.

For example, judging by this map, I'd say contrails are more likely to form over Cairo than over Crete:



Me thinks.

[LuvMyChicken]

It all depends on the conditions in the upper troposphere/ stratosphere. If it is cold and humid, you will get some killer contrails, but if it's dry, contrails will be small and disappear immediately behind the aircraft.

[saltine]

upper midwest usa.. consistant haze or "filtered sun". If I had wanted to go solar I'd be at a loss.. Still waiting for good seeing to use my scope, a rare occasion.

[saltine]

Originally Posted by Walshie79

They are a menace in Britain, forming large areas of imitation cirrus/cirrostratus cloud that can dim the sun for hours at a time. We get few enough clear days as it is and it is maddening to see one ruined by this pollution that nobody seems willing to combat (while things at ground level are subject to all sorts of petty rules and regulations).

Until the late 90s the only contrails we saw here were the thin lines behind planes that lasted minutes. You still get them, but just as often it's this new kind that form thick marks, that can spread out into what can be easily taken for cloud. It really has only appeared since about 1998, and it seemed to get much more common from about 2004. Either the composition of the air up there has changed or what's in the aircraft exhaust has. And someone needs to sort it out.

I've noticed them all my life but now that you mention it I dont recall them being so widespread and blanketing until the 90's

[Cambium]

Here's an aviation link Pilots use. They also use soundings as well from RAP or RUC model to see how the atmospheric column looks itself.

ADDS - Winds/Temps