SGS
No these Marfa Shear Waves have nothing to do with the Dry Line.
Or Cu.
As I recall we were almost always in the blue, and at the top of the Thermal, you would keep the nose up and poke around looking for this subtle bump, you'd know it when you found it. It went smooth and these areas were say, roughly, 1/2 mile by 1/2 mile. You would have to slowly drift with it and S turn and /or slowly 360 to stay in them. And these areas would drift at about 1/2 the wind speed.
It was pretty windy when we were doing all this.
They are differential wind direction induced.
They were easy to stay in, but it was windy during all this and you'd drift quite a ways downwind. In my Ka6 CR I'd have to leap frog forward to keep the airport in glide.
Fun times in Marfa.
We got to go see the "Marfa Lights" too which are really cool.
Goggle those things.
They had/ have grandstands set up next to the interstate to hang out on and watch, they are a trip to see in person.
Nick
T