NAO Index is following very similar behavior to last year.
I would like to better understand why we see -NAO tendency dominate fall, flip to +NAO tendency around the beginning of winter (end of December/mid January), and predominate through mid March...
As we know from an ENSO state, this year vs last is apples to oranges and yet, the NAO index is following very closely...
Something bigger may be going on here...
I know on the climate change side there has been a semi-permanent "cold pool" observed to be centered in the region of iceland, which is theorized to be driven by the slowing down of the gulf stream component of the AMOC. Perhaps the development and peaking of this "cold pool" coincides with the the near solar minimum, which in turn drives the NAO Index to positive tendency. The cold pool is relatively less by mid March as SST's in the North Atlantic achieve minimum, and ISR is more influencial to +temp anoms in this part of the world...