Unique high-resolution lightning and radar data have been acquired from a nonsupercell, hail producing summer thunderstorm over the Great Plains. The Principal Investigator will analyze the relationship between the storm's lightning activity and its dynamics and evolution; particularly to investigate the timing of lightning relative to precipitation growth, the lightning response to the production of large hail, and clues to the reasons why the polarity of the storm's electrical structure was not inverted. This hailstorm is one of the first to have been probed by the National Weather Radar Testbed Phased Array Radar (NWRT PAR), which supports rapid sampling (26 s to complete a sector volume scan) of the thunderstorm's radar reflectivity signatures. The radar reflectivity and velocity data reveal unprecedented detail of storm evolution, far superior to that provided by the traditional Weather Surveillance Radar 1988-Doppler (WSR-88D) Volume Coverage Patterns (VCPs). The Oklahoma Lightning Mapping Array (LMA) captured high-resolution lightning location data in three dimensions. The hailstorm evolved rapidly and was ideally placed for observation by both systems throughout its lifetime. Furthermore, it produced a clear three-body reflectivity spike that can be used to track the advent and descent of large hail. Thus, it will be possible to examine relationships of lightning to other evolving storm properties with unmatched temporal and spatial resolution.
Intellectual Merit: The study will examine a number of questions relating to lightning in storms. In particular, the researchers intend to examine why the storm had an apparently normal electrical polarity instead of the abnormal, inverted type that has been observed in other similar storms. Additionally, the relationship between hail and lightning activity and electrification will be investigated, as well as the relationship between significant lightning activity sometimes observed to precede severe weather at the ground. Other questions relating to the onset of lightning in relation to the initial storm dynamics are anticipated to be revealed using the higher temporal-resolution radar data.
Broader Impacts: It is anticipated from this analysis that evidence can be found for the credibility of whether lightning activity can be used in some situations as a precursor to imminent severe weather. Hypotheses about this will be directly examined and may have implications for severe weather nowcasting and the issuing of advanced warnings. More generally, this study will help in developing techniques to combine three-dimensional lightning and high-temporal resolution radar data for both research and practical applications.
