Inland Severe Weather Impacts Produced by Landfalling Atlantic Hurricanes in 2017

The 2017 Atlantic hurricane season was very active and destructive, with several landfalling tropical cyclones, including Hurricanes Harvey and Irma. These two hurricanes produced substantial impacts in Texas, Louisiana, and Florida, leading to significant loss of life and property. While many of the impacts associated with the landfall of Harvey and Irma were concentrated along the immediate coastline (e.g., storm surge, strongest sustained winds), other impacts, such as tornadoes and wind gusts, were observed further inland. In the case of Harvey, tornadoes and wind gusts compounded the danger imposed by widespread fresh water flooding which resulted in a very challenging forecast for the National Weather Service. In the case of Irma, dozens of tornado warnings were issued along the entire Florida Peninsula and damaging wind gusts were embedded within its rain bands, resulting in a perilous situation that lasted several hours in many locations. In this study, radar and surface wind data collected for Hurricanes Harvey and Irma are examined to evaluate the role that both tornadoes and wind gusts may have played in producing the inland damage that was observed for those two systems. In addition, numerical model forecasts are also evaluated to assess the potential predictability of severe weather in landfalling tropical cyclones.

Disclaimer: The views, opinions, and findings contained in this report are those of the authors and should not be construed as an official National Oceanic and Atmospheric Administration or U.S. government position, policy, or decision.