Rare Tropical Cyclones: Tropical Cyclone Hidaya, A High‐Impact Low‐Latitude Event
- 1Department of Atmospheric Sciences Texas A&M University College Station Texas USA
- 2Institute of Applied Physics, University of Bern Bern Switzerland
Abstract
Tropical cyclones pose significant hazards to coastal communities through destructive winds, intense rainfall, storm surge, and flooding. In May 2024, tropical cyclone Hidaya made landfall along the Tanzanian coast at an unusually low latitude (within ±7.5° of the equator), where tropical cyclone development and persistence are generally suppressed by weak planetary vorticity. This rare event provides a unique opportunity to investigate the atmospheric and oceanic processes that enabled cyclogenesis and maintenance in a marginal dynamical environment. Using atmospheric reanalysis, oceanic analyses, and storm‐centered diagnostics, we examine the environmental conditions governing Hidaya's evolution. Our results show that a weakened and southeastward‐displaced South Indian Ocean High modified the large‐scale steering flow, directing the cyclone westward and equatorward toward Tanzania. Simultaneously, anomalously warm sea surface temperatures and elevated tropical cyclone heat potential supplied sufficient upper‐ocean energy to sustain organized deep convection. Storm‐centered analyses reveal persistent low‐level cyclonic rotation, boundary‐layer convergence, abundant mid‐tropospheric moisture, sustained ascent, and relatively weak environmental wind shear that collectively maintained the cyclone despite limited Coriolis forcing. Structural diagnostics further indicate that enhanced diabatic heating promoted vertical coupling of the vortex through cloud–infrared radiation feedback, while the subsequent depletion of upper‐ocean heat content over shallow coastal waters contributed to storm weakening prior to dissipation. Historical analyses confirm that tropical cyclone landfalls of this nature remain exceptionally rare along the Tanzanian coast. By integrating large‐scale circulation, storm‐scale dynamics, and upper‐ocean energetics, this study provides a physically consistent framework for understanding how rare near‐equatorial tropical cyclones can develop and persist. These findings improve understanding of tropical cyclone behavior in marginal environments and have important implications for forecasting, hazard assessment, and disaster preparedness across coastal East Africa.
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BibTeX
@article{quagraine2026rare,
title = {{Rare Tropical Cyclones: Tropical Cyclone Hidaya, A High‐Impact Low‐Latitude Event}},
author = {Kwesi Twentwewa Quagraine and Loretta Pearl Poku},
journal = {Meteorological Applications},
year = {2026},
month = sep,
doi = {10.1002/met.70235},
url = {https://doi.org/10.1002/met.70235},
note = {CC BY},
}
RIS
TY - JOUR
TI - Rare Tropical Cyclones: Tropical Cyclone Hidaya, A High‐Impact Low‐Latitude Event
AU - Kwesi Twentwewa Quagraine
AU - Loretta Pearl Poku
PY - 2026
DA - 2026/09/01
JO - Meteorological Applications
DO - 10.1002/met.70235
UR - https://doi.org/10.1002/met.70235
AB - Tropical cyclones pose significant hazards to coastal communities through destructive winds, intense rainfall, storm surge, and flooding. In May 2024, tropical cyclone Hidaya made landfall along the Tanzanian coast at an unusually low latitude (within ±7.5° of the equator), where tropical cyclone development and persistence are generally suppressed by weak planetary vorticity. This rare event provides a unique opportunity to investigate the atmospheric and oceanic processes that enabled cyclogenesis and maintenance in a marginal dynamical environment. Using atmospheric reanalysis, oceanic analyses, and storm‐centered diagnostics, we examine the environmental conditions governing Hidaya's evolution. Our results show that a weakened and southeastward‐displaced South Indian Ocean High modified the large‐scale steering flow, directing the cyclone westward and equatorward toward Tanzania. Simultaneously, anomalously warm sea surface temperatures and elevated tropical cyclone heat potential supplied sufficient upper‐ocean energy to sustain organized deep convection. Storm‐centered analyses reveal persistent low‐level cyclonic rotation, boundary‐layer convergence, abundant mid‐tropospheric moisture, sustained ascent, and relatively weak environmental wind shear that collectively maintained the cyclone despite limited Coriolis forcing. Structural diagnostics further indicate that enhanced diabatic heating promoted vertical coupling of the vortex through cloud–infrared radiation feedback, while the subsequent depletion of upper‐ocean heat content over shallow coastal waters contributed to storm weakening prior to dissipation. Historical analyses confirm that tropical cyclone landfalls of this nature remain exceptionally rare along the Tanzanian coast. By integrating large‐scale circulation, storm‐scale dynamics, and upper‐ocean energetics, this study provides a physically consistent framework for understanding how rare near‐equatorial tropical cyclones can develop and persist. These findings improve understanding of tropical cyclone behavior in marginal environments and have important implications for forecasting, hazard assessment, and disaster preparedness across coastal East Africa.
SN - 1469-8080
SN - 1350-4827
ER -