Philip, it's not the blocking per se I was picking up on but the way the cold
polar vortex seems to have shifted quite a bit from it's climatological position...
BTW I was having a look at this as well and came across this page with extensive polar vortex data
and diagnostics-
http://www.pa.op.dlr.de/arctic/
see also-
http://www.atmos.washington.edu/~hakim/tropo/tropo.html


--
regards,
david