American Airlines Virtual

I see these quite often. Especially when running AV6 and Rex clouds in FSX.

I equate it to Virga Rain, or least I like to believe it is.

In meteorology, virga is an observable streak or shaft of precipitation that falls from a cloud but evaporates before reaching the ground.At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is usually due to compressional heating, because the air pressure increases closer to the ground. It is very common in the desert and in temperate climates. In North America, it is commonly seen in the Western United States and the Canadian Prairies.

FS is a great make believe world to go into.

Yup, Wayne is correct. Virga associated with Cirrus clouds. We see that from time to time while flying and typically will deviate around it as it's typically turbulent. In this pic you have a line of colder, descending air. See the less developed cirrus clouds to the left of the photo. Probably a bit bumpy due to the shear of descending air. How bumpy is hard to determine so it's best to try to give yourself a bit of space or call ahead to get ride reports.

Cheers