Analysis of abnormally frequent cloud‐to‐ground lightning in Guangdong in April 2024: Roles of cloud microphysics, atmospheric circulations, and external forcings

Abstract Under global warming and enhanced ocean–atmosphere interactions, Guangdong Province, China, experienced an unprecedented cloud‐to‐ground (CG) lightning outbreak in April 2024. The lightning density reached 10.26 flashes·km −2 , 5.3 times the 2015–2023 April mean and even higher than summer climatological peaks. Using lightning observations, radar, sounding, ERA5 reanalysis, and HadISST data, combined with correlation/regression analyses, multivariate empirical orthogonal function (MV‐EOF) analysis, and Mann–Kendall tests, this study investigates the underlying mechanisms focusing on cloud microphysics, atmospheric circulation, and sea surface temperature anomaly (SSTA) forcing. Results show that the extreme event resulted from synergistic effects of cloud microphysical, dynamic, and thermodynamic conditions. Abnormally enhanced upper‐tropospheric ice phase particles and intense updrafts established a favorable vertical structure for lightning electrification, supported by higher convective available potential energy (CAPE) and elevated radar echo tops. Intensified low‐level and upper‐level jets jointly enhanced water vapor transport and upward motion. A decaying El Niño contributed to an anomalous Philippine anticyclone and moisture transport. A significant regime shift around 2005 indicates an increasing influence of the northern Indian Ocean on lightning over South China, independent of the El Niño–Southern Oscillation (ENSO). The 2024 Indian Ocean warming guided the jet stream to intensify dynamic lifting. Warm SSTAs in the Southern Hemisphere provided positive feedback. This study clarifies the cross‐scale mechanisms and highlights the critical role of dynamic lifting, providing a scientific basis for regional lightning prediction under global warming.