2005 on a site called easternuswx, elaborate research was done with North Atlantic SSTs, showing high lagging predictive value for following Winter's NAO/AO. The correlation factor was higher than 0.4, and there was advantage over decadal cycles. Meaning, it would predict years that reversed the decadal trend. The index was very accurate in predicting the +NAO for the 2005-2006 Winter, and got much attention after a topic called "This will be the warmest Winter on record for the US" (It was 7).