Ionospheric disturbances preceding severe weather on 23 October 2021 over Brazil

Traveling Ionospheric Disturbances (TIDs) are produced during thunderstorms, but the measurable nature of their cause-effect relationship remains unclear. Recent studies connect them to lightning-producing clouds and report their formation 8-10 minutes after a lightning jump, an onset condition of severe thunderstorms. The present study reports another set of Total Electron Content (TEC) disturbances from a thunderstorm event on 23 October 2021, preceding the lightning jump by a lead time of 20-40 minutes. With an amplitude of 0.5 TECU and a detection time of 8-10 minutes from the lightning flash rate (LFR) spectral peak in the 3-6 mHz band, the observed and simulated TEC disturbances favor the coupling energetics of acoustic-gravity wave (AGW) excitation from weak lightning-producing convective clouds. This study highlights the importance of LFR and TEC monitoring in the spectral domain during low-level LFR activity that often precedes severe weather.