Variations in the Intensity and Spatial Extent of Tropical Cyclone Precipitation

The intensity and spatial extent of tropical cyclone precipitation (TCP) often shapes the risk posed by landfalling storms. For example, the intensity and vast footprint of 2017’s Hurricane Harvey’s rainfall contributed to several days of flooding in Texas, multiple fatalities, and $11 billion in economic losses. Here we provide a comprehensive climatology of landfalling TCP characteristics as a function of tropical cyclone strength. We use daily precipitation records from the Global Historic Climatological Network – Daily (GHCN-D) station network and Atlantic US landfalling tropical cyclone tracks from the revised Atlantic HURricane DATabase (HURDAT2) from 1900-2017. Using a recently developed geostatistical framework, we directly analyze the intensity and spatial extent of ≥ 1 mm/day TCP (Z₁) and ≥ 50 mm/day TCP (Z₅₀) from station and tropical cyclone track data. We show that the highest intensity and largest spatial extent of Z₁ and Z₅₀ occur for landfalling major hurricanes when they weaken to tropical storms, indicating greater flood risk despite weaker wind speeds. We also find some signs of TCP change in recent decades. In particular, for landfalling major hurricanes that have weakened to minor hurricanes and tropical storms, Z₅₀ intensity has significantly increased, indicating possible increases in flood risk to coastal communities in more recent years.