Some clouds are thicker than others...but flying close / fingertip is a basic fighter task, learned in UPT. The worst position is to be #4, flying off of #3, who is flying off of #1. If #1 is rough then #3 is going to be rougher and #4 is going to have a hard time. It's all about anticipating turns, power changes, and making small corrections. Watch the Thunderbirds or Blue Angels...they are very close and look like they are glued together but they are making lots of very small corrections that the crowd can not see. Air refueling in the soup is similar...and tankers are very good at finding in the only clouds in the AR track.
Now...flying formation in the clouds at night...is another story.