On the spatial patterns of intense tropical cyclones: A case study of Charleston, South Carolina (USA)

The characteristics and conditions favoring extreme hurricanes remain largely unknown due to their small number in the observational record. Synthetic tracks are capable of providing a large, representative sample of these events, which provides an opportunity to further our understanding of extreme characteristics as compared to more common tropical cyclones. We compare 300 synthetic extreme (100-year event, 48.9 m/s) and common (5-year event, 33.6 m/s) tropical cyclones for Charleston, South Carolina for differences in spatial, temporal, and other characteristics. Results suggest that extreme hurricanes have a more defined spatial and temporal behavior, generally forming off the coast of Africa and making a direct landfall in Charleston. Common tropical cyclones sometimes make prior landfalls, may approach from either the Gulf or the Atlantic, and often decay well before reaching Charleston. They are likely to occur through much of the hurricane season, while extreme events are most common during a short period toward the end of August. There is no significant difference between common and extreme translational velocity at landfall. This study demonstrates the opportunity that synthetic tracks provide for understanding the most rare hurricanes, and provides initial insight into those affecting Charleston.