On the Systematic Occurrence of Compound Cold Spells in North America and Wet or Windy Extremes in Europe

The repeated co-occurrence of cold spells over Eastern North America and wet or windy extremes over Western Continental Europe during recent winters, has led to hypothesize a link between the two. Here, we analyze the interplay between the large-scale atmospheric circulation and co-occurring cold spells in North America and wet or windy extremes in Europe. We collectively term these occurrences compound cold-wet-windy extremes. We leverage a recent approach grounded in dynamical systems theory, which provides an analytically and computationally efficient analysis of spatially resolved, multivariate climate extremes. We find that there are specific, recurrent large-scale atmospheric circulation patterns systematically associated with both the individual extremes and co-occurring cold-wet-windy anomalies. Evidence for this is also found when focusing on compound cold-wet-windy extremes, although with a weaker signal. This motivates further analyses focusing specifically on the statistics and drivers of these compound extreme occurrences.