loading page

Cascading weather events amplify the coastal thermal conditions prior to the shelf transit of Hurricane Sally (2020)
  • +3
  • Brian Dzwonkowski,
  • Severine Fournier,
  • Grant Lockridge,
  • Jeff Coogan,
  • Zhilong Liu,
  • Kyeong Park
Brian Dzwonkowski
University of South Alabama, University of South Alabama

Corresponding Author:[email protected]

Author Profile
Severine Fournier
Jet Propulsion Lab (NASA), Jet Propulsion Lab (NASA)
Author Profile
Grant Lockridge
Dauphin Island Sea Lab, Dauphin Island Sea Lab
Author Profile
Jeff Coogan
Woods Hole Oceanographic Institution, Woods Hole Oceanographic Institution
Author Profile
Zhilong Liu
University of South Alabama, University of South Alabama
Author Profile
Kyeong Park
Texas A&M University at Galveston, Texas A&M University at Galveston
Author Profile


Changes in tropical cyclone intensity prior to landfall represent a significant risk to human life and coastal infrastructure. Such changes can be influenced by shelf water temperatures through their role in mediating heat exchange between the ocean and atmosphere. However, the evolution of shelf sea surface temperature during a storm is dependent on the initial thermal conditions of the water column, information that is often unavailable. Here, observational data from multiple monitoring stations and satellite sensors were used to identify the sequence of events that led to the development of storm-favorable thermal conditions in the Mississippi Bight prior to the transit of Hurricane Sally (2020), a storm that rapidly intensified over the shelf. The annual peak in depth-average temperature of >29°C that occurred prior to the arrival of Hurricane Sally was the result of two distinct warming periods caused by a cascade of weather events. The event sequence transitioned the system from below average to above average thermal conditions over a 25-d period. The transition was initiated with the passage of Hurricane Marco (2020), which mixed the upper water column, transferring heat downward and minimizing the cold bottom water reserved over the shelf. The subsequent reheating of the upper ocean by a positive surface heat flux, followed by a period of downwelling winds, effectively elevated shelf-wide thermal conditions for the subsequent storm. The climatological coupling of warm sea surface temperature and downwelling winds suggest regions with such characteristics are at an elevated risk for storm intensification over the shelf.
Dec 2021Published in Journal of Geophysical Research: Oceans volume 126 issue 12. 10.1029/2021JC017957