Temporal Clustering of East Coast Cyclones

Temporal clustering of cyclones has been shown to create dangerous weather over the exit region of the North Atlantic storm track. Herein, we explore the statistical behavior of cyclone tracks and large-scale circulation associated with temporal clustering of cyclones over eastern North America. Through an analysis of tropical cyclone and extratropical cyclone tracks, we identify the time periods of clustering events for our region. For the clustering events we detect, there is no statistically significant difference for track lifetime, track speed and path for cyclones involved in cluster events as compared those not in clusters. However, there are differences in the large-scale circulation during cluster events as compared to the circulation during cyclone events that are isolated temporally. Using reanalysis data, we determine that there is distinct upstream and downstream organization of the atmosphere, in terms of sea level pressure, zonal wind, and Rossby wave breaking during cluster events. These could potentially be a basis for predicting cluster events by considering the jet stream anomalies over the large region when a storm approaches Eastern North America. However, we also determine that the clustering events for our study region do not involve the same part of Rossby wave breaking that re-enforces clustering over Western Europe and the British Isles.