well I guess the NAO is negative, specifically if think that one of the ways to express the NAO index is the SLP anomaly in Ponta Delgada, Azores Islands, minus the SLP anomaly in Iceland
and the AO index, which is effectively calculated by SLP (really, 1000mb heights) shows a very negative value today
December 1-8 analysis shows a strong negative NAO value and yet the eastern USA had higher than normal heights at 500mb