Charge structure comparison of thunderstorms that experience synoptic-scale vs. mesoscale forcing: UPLIGHTS, DC3, and NMT storms

UPLIGHTS was a three-year study in Rapid City, SD that utilized high-speed optical and electric-field sensors to study upward lightning from tall towers, as well as energetic, sprite-producing cloud-to-ground (CG) lightning. In its final year of operation (2014), UPLIGHTS added a 9-station New Mexico Tech Lightning Mapping Array (SDLMA) to its existing sensor suite. The purpose of this paper is to compare the synoptically-forced lightning-producing storms of late spring/early summer with those that are produced by mesoscale (smaller-scale) forcing in mid to late summer in western South Dakota. In particular, we document the kinds of electrical structures observed in the two storm regimes using SDLMA data. The results are contrasted with data from the New Mexico Tech (NMT) LMA that has been operated by Langmuir Laboratory since the late 1990s, as well as with results from the 2012 Deep Convective Clouds and Chemistry (DC3) project in north-central Colorado. Central New Mexico storms have been shown to be predominantly of normal polarity; in contrast, preliminary results from DC3's 15-station LMA network showed that local charge structures were predominantly anomalous. The charge structures of similar storm morphologies from each geographic location--western South Dakota, central New Mexico, and north-central Colorado--will be compared.