At the risk of boring other forum readers, I’d like to make a few further comments so that anyone interested doesn’t have a mistaken impression of wave systems. Besides, I rarely get to have a discussion with someone about obviously knows something about it :-).
With sufficient moisture present, clouds can form (including standing altocumulus lenticularus) at the top of the rotors. Mountain waves occur anytime you get a strong flow over the ridge. <
Agree with this, but only because the lenticular clouds happen to be at the peak of the waves and the lower level rotor turbulence underlying the wave system happens to be underneath the wave peaks as well. To have the correct understanding of a mountain wave and the clouds associated with it, I didn’t think it appropriate to say the lenticular clouds were located at the top of the rotor, they are actually interspersed at various altitudes in each of the waves. A fine point, but worth mentioning.
By definition a mountain wave must have a non-convective, stable environment. <
Well, I would only like to add that the stable non-convective environment must be present only at the altitudes where the wave system is occurring. I have ridden strong thermals many times up into wave systems. As a matter of fact, that is about the only way I could get to them because I was too cheap to pay for a high tow behind the Pawnee. Usually, you could not get to the wave until you get to about 5,000’MSL, and that is anything but a stable air mass around here. That is a great day for soaring! I know that sometimes, the mountain wave system was not organized and laminar until you were at or near the inversion, where the air became isothermic or stable. But, there was clearly ovelap between the convective altitudes and wave altitudes. In many cases, I am confident the wave system could have been organized at lower altitudes if the inversion had been at a lower altitude. This demonstrates your point about wave systems occurring only in stable air, but it left the impression that if a guy took off and climbed through a lot of convective activity, he would not have to worry about wave at all.
When you get orographic lifting as air flows up and over a mountain during an unstable or conditionally unstable atmosphere it can cause rising air to continue to rise. But I would say that this is a different process and not classified as a “mountain wave.” In other words, I wouldn’t expect to feel any wave effects “downstream” of this rising air. <
As you probably already know, orographic lifting is a function of surface winds and obstacles to their movement. For mountain wave to develop, these surface winds must be supported by mid and upper level winds from more or less the same direction. I would agree that if they are not supported by the mid & upper level winds, you would not expect a wave system to form with any significant tertiary waves.