The North Atlantic climate variability is mainly regulated by the North Atlantic Oscillation (NAO), one of the most important patterns of atmospheric circulation variability. It has a strong influence on surface climate over this region with a marked impact on the environment, society and economy. Thus, it is of paramount importance to deepen our understanding of it and its governing mechanisms. In this work I have analysed both observed variability using ERA5 reanalysis (1950-2023) and the simulated variability through a set of twin simulations, provided by the meteorology group of the University of Barcelona, performed with the standard configuration of EC-EARTH3 global climate model (GCM) for CMIP6.