When someone says "If X happens then Y may/can happen" what does he mean? He means what are the possible scenarios or the probable scenarios? Should we use may or can interchangeable in such sentences?
"Possible" sounds like exploring and identifying the full horizontal trade space of how an object ("scenarios" in this case) can be manifested.
"Probable" sounds like a subset of the "Possible" elements that have higher probability of occurring. In other words, Probable sounds stronger and more resolute than Possible.
Higher probability of a scenario happening among all the possible events...
Just my impressions... although,,, I'm now being swayed to think, having written above, that they might be conveying exactly the same thing.