It looks to me like the the system from the 20th drives up near Greenland and congeals into a PV, which explains the + flip in the polar domain.....and I mean, at some point I guess the cold will need to be replenished and the pattern resets. I understand why the temp hitting 60 instead of 50 is due to CC (this is not disputed....huge posotive departures are more common), but the sequence itself I don't feel is. I still bet a lot of money that blocking redevelops in February and is paired with a better Pacific than we had in January and certainly February.