On 31 March 2016 (IOP 3), a tornadic supercell evolved within the ARMOR and MAX southern dual-Doppler lobe producing an EF-2 tornado. The supercell possessed lightning flash rates less than 28 flashes minute-1throughout its lifespan, but a lightning jump was observed 16 minutes prior to tornado formation. Previous studies suggest the presence of a lightning jump is associated with the strengthening of a storm’s updraft speed and volume, followed by severe weather. However, a sudden decrease in lightning flash rates (or a “negative lightning jump”) occurred 8 minutes after the initial positive lightning jump. These decreases in lightning flash rates before the onset of severe weather have been observed in previous studies, but limited research has been performed to understand their importance, especially in tornadic storms.
Dual-Doppler radar analysis will be presented to show how updraft and downdraft characteristics evolve with respect to total lightning flash trends and dual-polarization inferred microphysical signatures. In addition, the evolution of the 31 March 2016 tornadic supercell event and the 30 April 2016 nontornadic supercell will be compared to help distinguish if unique lightning signatures and associated physical and dynamical processes can be identified in each storm. Relationships between storm kinematics, microphysics, lightning and tornadogenesis will be explored with a special emphasis on developing a better understanding of the causes and implications of the negative lightning jump.