Thunderstorm characteristics with lightning jumps and dives in satellite-based nowcasting

Abstract

Abstract. The first Meteosat Third Generation (MTG) satellite was launched in December 2022. Its high resolution Flexible Combined Imager (FCI) in combination with the Lightning Imager (LI) herald a new period for geostationary (GEO) weather observations over Europe, Africa, and adjacent regions. Similar instruments are already operational over the U.S., with the Advanced Baseline Imagers (ABIs) and the Geostationary Lightning Mappers (GLMs). The objective of this study is to gain a deeper understanding of GEO data, with a specific emphasis on sudden increases in a storm's lightning activity, referred to as lightning jumps (LJ), and decreases, known as lightning dives (LD), as observed from a geostationary orbit. ABI-based cloud characteristics of thunderstorms are analyzed while storms are categorized by whether they produced LJs, LDs, or severe weather. It is found that the storms with LJs and/or LDs feature overall similar characteristics as the severe thunderstorms. Those storms typically feature elevated, colder cloud tops, more and stronger overshooting tops (OTs), consequently leading to more structured updrafts. As a result, these storms tend to generate higher convective rain rates (CRRs) on average compared to storms lacking LJs, LDs, and those categorized as non-severe. In particular, thunderstorms experiencing multiple LJs throughout their lifecycle exhibit the most and strongest OTs, signifying highly organized updrafts, extremely cold cloud tops, and highest CRRs. Considering the characteristics mentioned above, these storms, especially those featuring multiple LJs and LDs during their lifecycle, are of particular interest for nowcasting potentially dangerous weather phenomena.