Bob,   Posted this elsewhere in reply to a strat inquiry, and it is pertinent here. I think the most salient question at this point is trop-strat coupling and consequently the propagating effectiveness of a w-2 induced split to materially alter the troposphere. One of the most significant predictors of whether tropospheric blocking will occur following SSW is if tropospheric blocking exists prior to the event.   1. All stratospheric events -- displacements, splits, are highly