Impacts of Storm Track Variations on Cold Season Extreme Weather Events over the Continental United States

Mid-latitude cyclones give rise to synoptic scale weather developments and are dominant drivers for cold season extreme weather events such as high winds, heavy snow, and extreme cold. Thus how storm track variations impact extreme weather events is important to quantify. Moreover, under global warming, most Coupled Model Intercomparsion Project Phase 5 (CMIP5) models project a significant reduction in storm track activity over North America. It would be of interest to explore how such changes may impact the frequency and intensity of future extreme weather events.

In this study, we make use of observed and reanalysis data sets to examine the signature features of different variables both in defined strong and weak storm track composites. The selection of storm track as a divider is physically reasonable as storm track variation is one of the main drivers. The difference between the high and low composites not only shows the effectiveness of the partition itself, but also indicates a pattern of future change, whose value could be regressed from the CMIP5 model ensemble projected storm track change.

In this presentation, we will show a contrast between the east coast and inland regions of the US through their responses to storm track variations. The response patterns of extreme precipitation, high winds, and extreme cold show a consistent relationship. And this location contrast might imply different local mechanisms acting on extreme weather during US winters.