An Observational Study of Short‐Cycle Lightning Outbreaks in the Inner Core of Typhoon Hato (2017) Before Landfall

Abstract

Abstract This study analyzes microphysical signatures relevant to the short‐cycle lightning activity in the inner core of Typhoon Hato (2017) before landfall in China. Observations reveal that the lightning bursts were accompanied by enhanced inner‐core convection with a behavior cycle of about 3 hr. The coupling between wavenumber‐2 vortex Rossby waves (VRWs) and shear‐forced convective asymmetries resulted in a local updraft enhancement. Furthermore, supercooled liquid water droplets invigorated a striking enhancement of graupel via riming immediately above the freezing level, further enhancing charge separation and lightning generation outside the eyewall. Furthermore, when similar phase‐locking was associated with other propagating VRWs, graupel and updraft volumes were significantly boosted, leading to short‐cycle lightning outbreaks in the inner core.

Keywords

• tropical cyclones
• radar
• lightning
• quasi‐periodic
• vortex Rossby waves
• vertical wind shear