Comparison of Extreme Coastal Flooding Events Between Tropical and Mid-Latitude Weather Systems in the Delaware and Chesapeake Bays for 1980 – 2019

Abstract Coastal flooding is one of the most costly and deadly natural hazards facing US Mid-Atlantic region today. Impacts in this heavily populated economically significant are caused by a combination location’s exposure forcing from storms sea-level rise. Tropical cyclones (TCs) mid-latitude (ML) weather systems each have extreme coastal region. Skew surge was computed over tidal cycle for past 40 years (1980 – 2019) at several tide gauges Delaware Chesapeake Bays to compare meteorological component type. Although TCs cause higher mean surges, ML can produce surges just as severe occur much more frequently, peaking cold season (November March). Of top 10 largest events, account 30-45% upper 40–45% lower Bay. This percentage drops 10-15% larger numbers events all regions. Mean pressure 500 hPa geopotential height (GPH) fields show low-pressure center west-southwest Delmarva semi-stationary high-pressure northeast prior maximum surge, producing strong easterly winds. Low-pressure centers intensify under upper-level divergence they travel eastward, near GPH ridges. During bay develop further south, intensifying warmer waters, with south-shifted pattern compared events.