Evolution of convective events as indicated by total lightning within three major hurricanes during periods of rapid intensification

Rapid hurricane intensification has the potential to induce large loss of life. Unfortunately, the physical processes that lead to rapid intensification intimately depend on small-scale hard-to-forecast convective events occurring within the hurricane eyewall. Thus, a key aspect for recognizing the onset of a rapid intensification cycle is to continually observe the evolution of the convective events. Though atmospheric data obtained from hurricane hunter aircraft are invaluable for observing some of these events, these data streams are not continuous and hence can miss important convective events. As will be illustrated in this talk, we believe an important data source that can be used to fill in the aircraft data void is lightning. To demonstrate the utility of lightning to map out the evolution of convective events in the hurricane eyewall, lightning data obtained from Los Alamos' Sferics Array (LASA) for three Atlantic major hurricanes will be presented. To help illustrate the importance of this information for possibly predicting rapid intensification, lightning data was categorized within the following three key topics: 1) The mapping of various lightning types within the hurricane eyewall and the abrupt increase in lightning count prior and during rapid intensification; 2) the general increase in height of a specialized lightning type, the narrow bipolar event, during rapid intensification; and 3) the evolution, as indicated by lightning, of select convective elements in the eyewall. The last topic is particularly revealing and suggests that the general increase in height of lightning, highlighted in topic two, is an aggregate consequence of numerous short-lived convective events rapidly rotating around the eyewall. This raises important questions with regard to the community's ability to predict hurricane intensification. Chief among them is whether hurricane models must accurately resolve the evolution of the convective events or just capture the integrated impact of these events on the overall intensity of the eyewall convection.