What I'm looking at, where considering your response to the idea suggested by "weather2plan" above (if somewhat sketchy, certainly fairly general), where looking at a (/ any type of more.) cyclical regularity where considering broader weather patterns, .. is basically, that "blocking" could - logically, also be looked at as occurring / being brought about .. cyclically.
Or in other words, and in more direct response to what you've said more just above, .. With "blocking" being a product of the both speed of movement, together with variable amplitude, of the waves (various ridges and troughs) in the jet, .. what's to say that these elements don't also occur with some type of cyclical regularity. ?