Is the NAO winter index a reliable proxy for wind climate and storminess in northwest Europe?

Climate measures synthesized from the instrumental wind record at 53 stations in northwest Europe are compared with various derivations of the North Atlantic Oscillation (NAO) winter index. The NAO is highly correlated with wind direction frequency, with positive phases in the NAO winter index associated with increased frequency of winds from the southwest. These correlations are sensitive to the choice of winter period and diminish with longer period, especially the inclusion of October. Evidence for connections between the NAO and wind speed or storminess measures is far less convincing, particularly in terms of the frequency of extreme wind speed events. These results have important implications for the use the NAO winter index as a proxy for storminess, whether in palaeoenvironmental reconstructions or as a basis for storm forecasting.