Exploring a possible connection between U.S. tornado activity and Arctic sea ice

The significant losses in Arctic sea ice over the past few decades appear to have been accompanied by changes in global-scale and regional-scale atmospheric circulation. Such circulation changes have in turn been used to support arguments that low Arctic sea-ice extent (SIE) has helped to promote extreme weather events within the mid-latitudes. The contemporaneous variability in U.S. tornado incidence over the past decade provides motivation to explore whether the essence of these arguments also applies to tornadoes. Here, robust statistical correlations are found between tornado activity and SIE during boreal summer, specifically in July. The statistical relationship is supported by the presence of anomalous regional circulation and storm track that are unfavorable (favorable) for tornado-bearing thunderstorm formation when SIE is low (high).