This is what we use to forecast contrails in Australia, in the tropics where I am it is less likely for contrails to form, than it is in the mid
First off we need very cold and humid air. Temperature is a prime factor, in that if the temperature is warmer than approx -34 degrees celsis, then
there is a zero percent chance of contrail development. Next factor is humidity. There is a zero percent chance of contrail development if the
humidity is less than 40%. The chance increases as the air is moister because supersaturation is liklier to occur with more water and ice in the
We determine air saturation and temperature by releasing radiosondes whihc are attached to weather balloons. The results are plotted on whats called
an F160 or more commonly a skew T diagram.
Persistant contrails occurrence depends on the position of whats called the tropopause. The tropopause is the boundary that seperates, the
stratosphere from the troposphere and is also the point at which the temperature stops decreasing an starts increasing again. In mid latitudes the
tropopause is usually located in between 25,000ft and 35,000ft but is not always at a set height. The air below the tropopause can be frequently
saturated with ice crystals while the air above it is frequently very dry.
Planes crusing below the tropopause will form persistant contrails when the air temperature is below -36 celsius (which is ALWAYS, no exception, check
any skew T diagram to prove me wrong if you dare). Planes cruising above the tropopasue have a very unlikely chance of producing persistent contrails
as the air is too dry for supersaturation to occur, thus contrails dont last for long.
When a plane passes through moist cold air, the hot water vapour in its exhaust freezes, the process usually takes less then a second. If there is ice
crystals in the air (ie cold humid air), the water from the exhaust attaches itself to the ice effectively increasing it size and giving us on the
ground a view of a white line. If a persistent contrail does from, there is a high likelyhood of cloud development in the coming hours. It is a good
forecast tool to use for amatuer weather observers
Using data from the skew t diagrams, wind shear can be determined. This can spread the cirrus cloud into a layer, known to us as cirrostratus which
spreads across the sky. Cirrostratus is often a precurser to rain as it suggests instability and a high presence of water vapour in the air
Now can someone please explain to me how/why chemicals allegedly sprayed by secret government organisation persist in the sky and spread out? Also
try to explain....using your knowledge of meteorology, which you apparently all have....why water vapour will not do this.
And please use scientific answers...pictures and youtube videos are not acceptable