Abstract
This paper expands on work showing that the winter North Atlantic
Oscillation (NAO) is predictable on decadal timescales to quantify the
skill in capturing the North Atlantic eddy-driven jet’s location and
speed. By focussing on decadal predictions made for years 2-9 from the
6th Coupled Model Intercomparison Project over 1960-2005 we find that
there is significant skill in both jet latitude and speed associated
with the skill in the NAO. However, the skill in all three metrics
appears to be sensitive to the period over which it is assessed. In
particular, the skill drops considerably when evaluating hindcasts up to
the present day as models fail to capture the latest observed northern
shift and strengthening of the winter eddy-driven jet and more positive
NAO. We suggest the drop in atmospheric circulation skill is related to
reduced skill in North Atlantic Sea surface temperature.