Globally (NH), we have gone through a remarkably long stretch of a relatively flat flow with zero blocking, no persistent large-scale amplified trough / ridge couplets; no real anchor features; true arctic air has not be a regular visitor to the middle latitudes anywhere across the NH. Why??? I have no clue. Even in many of our blah / ratter winters, there were strong features causing havoc elsewhere; this year not so much. The oceans are very warm on a widespread basis though and maybe the lack of sst gradients are playing a role???