Hi all,

I wonder if anybody could offer some advice on contrail observation?
When conditions are right and contrails are long lasting and spread
out to lead to Cs or Ci layers do they cease to be contrails for the
purpose of cloud classification and reporting? For example, on a day
with no naturally formed cirriform clouds but with contrails that
develop into a 3 okta Cs/Ci cloud cover should this be recorded as 3Ci
or 3Cs along with a RMK that they evolved from contrails, or is it the
case of once a contrail, always a contrail and a RMK made along the
lines of "Extensive contrails, spreading to form Cs/Ci" with no
comment made upon the extent of cloud cover? I observe many contrails
being situated under several flight paths. I would be very grateful
for some guidance on how one should classify and report man made
cirriform.

Many thanks,

Ian,

Raunds, East Northants. 63m. Grid Ref SP9972
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