When two systems (maybe systems is the wrong word) collide? This question is presented in a meteorological sense, but I imagine it applies to almost any interaction between two dynamic systems. Any and all examples or leads into this phenomenon (outside of purely mathematics) would be interesting and appreciated... **My question** Correct me if I'm wrong, but at least over the continental US two different storm systems (or cells), one having a low pressure and warm air and the other having high pressure and cold air, merge in pursuit of an equilibrium. But what mechanisms guide this interaction and the interactions between any two similar objects moving at each other like pressure cells? I imagine they "cancel out" in some sense, but what rules guide the various aspects of this cancellation like change in velocity, momentum, pressure etc.? I am not as much concerned about temperature of the air as I am about the interaction between the two different pressures (although they might be related)... Here's what I think happens: Obviously, the two systems will seek equilibrium in both pressure and temperature. I would imagine that this occurs in different forms and produces different outcomes (tornadoes, cold fronts, etc), but what I am primarily concerned with is how much the momentum (or maybe its power?) each cell loses as a result of the collision. Another version of the same phenomena in question, What happens if you shoot two sound waves of the same magnitude at each other? Will they cancel out or just merge into a 3rd combined form? Thanks a lot!