this has been confirmed to be the con trail of a jet taken off the gulf coast back in may. now let's put them side by side. you can decide for yourself. the left taken yesterday on the right taken off the gulf coast. that is a jet engine which is why some experts are saying what you see on the left may be with a jet con trail though nobody has come out to confirm that for us yet tonight, shep. >> shepard: it's my understanding that weather can effect those con trails? >> weather plays a big factor because what really helps or hurts these things is humidity and wind. we went back and checked and yesterday off the coast of catalina, it was 84% humidity and the winds were very high for southern california this time of year the reason the winds play a big part is the winds can make that con trail at the base look a lot bigger than it normally would and the humidity gives it a lot more hep. the particles kind of condense.