May 22 - July 30
Lightning Hole and Lightning Jump Relationships in the PERILS Campaign
Alaina A. Adderley, Vanna C. Chmielewski, and Sarah M. Stough
What is already known:
- Lightning jumps are a potential indicator of storm intensification.
- Lightning holes can be indicative of a strong updraft.
What this study adds:
- Lightning holes exist not only in isolated supercells but also in quasi-linear convective systems.
- The lightning hole in this study began in the mid-levels of the storm and expanded vertically from there. The storm exhibited similar behavior in flash rate during both vertical expansion of the lightning hole as it developed and its contraction at the end of its life.
- This cell exhibited an varying flash rates, where the duration of the vertical expansion/contraction occurred during a time of decreasing flash rates, but many of the times the altitude changes whose flash rates briefly increased.
Abstract:
Lightning holes and lightning flash rate patterns, including jumps and dives, are known to be related to a storm’s updraft intensity. However, relationships between these spatial and temporal lightning patterns are not well defined despite their common dependency on the updraft. Understanding these patterns could help with early warnings and forecast confidence. This paper analyzes a storm observed in Mississippi and Alabama during the Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaign using Lightning Mapping Array (LMA) and radar data. This storm initiated ahead of and eventually merged with a quasi-linear convective system (QLCS). This evolution is especially interesting as lightning hole presence in QLCSs and mixed-mode storms has not been well documented in prior publications. The presentation of the lightning hole changed, with respect to altitude, as the merge occurred.. In this case, the lightning hole initiated in the mid-levels of the storm and expanded vertically. During these vertical expansions and contractions of the lightning hole, the flash rates varied alternatively between increasing and decreasing patterns. When the flash rates were at their highest, after the merge into the QLCS, the lightning hole was present throughout the deepest layers of the storm.