A long‐term climatology of North Atlantic polar lows

A dynamical downscaling of the 6‐hourly 1948–2006 NCEP/NCAR re‐analyses for the subarctic region of the North Atlantic has been used to derive a climatology of polar lows by means of a tracking algorithm based on the simulated bandpass filtered MSLP‐fields. This climatology is consistent with the limited observational evidence in terms of frequency and spatial distribution. The climatology exhibits strong year‐to‐year variability but weak decadal variability and a negligible trend. A Canonical Correlation Analysis describes the conditioning of the formation of polar lows by characteristic meridional seasonal mean flow regimes, which favor cold air outbreaks and upper air troughs.