Blocking Lows spawn little Lows which then run off an leave em
And little Lows then come to blows where ere the big Lows heave em
So what the name of of such events (so rare in my experience)
I wish to discuss the phenomenon that just made it's appearance?

Actually they are not that rare. I can't remember when or where I read about the phenomena but they tend to occur before something even more interesting, so I though I ought to bother.