Friday, 1 September 2023: 9:30 AM
Great Lakes BC (Hyatt Regency Minneapolis)
Mesovortices in quasi-linear convective systems (QLCSs) pose a substantial forecast challenge due to the speed at which they can develop and the difficulties in observing them. In the past decade, advancements in weather radar, such as the dual-polarization upgrade, have provided new and potentially useful data for forecasters to use during severe weather events. However, uncertainty remains in terms of exactly what information new radar data can add to the warning decision process and how these new data fit in with current observational radar- and environmentally-based conceptual models. Therefore, the purpose of this study is to examine primarily dual-polarization radar signatures that might provide information about QLCS mesovortex development and intensity. Two single-polarization radar signatures are also examined.
An analysis of 145 mesovortices—92 tornadic and 53 nontornadic—reveals promising results for using some dual-polarization radar signatures to inform warning decisions regarding QLCS mesovortices. Statistically significant differences exist between the midlevel and low-level specific differential phase (KDP) cores of mesovortices with varying classifications of impacts (e.g., tornadic vs. nontornadic). In addition, the KDP core, especially at midlevels, frequently develops before the mesovortex does, so it could help forecasters anticipate mesovortex development before it occurs. Another near-surface signature known as a KDP drop was also present before nearly every mesovortex in this dataset and there appears to be a preferred location relative to this feature for mesovortex development, which could help forecasters anticipate where a mesovortex could develop. In contrast to the potential usefulness of KDP signatures, nearly no statistically significant differences existed between the differential reflectivity (ZDR) columns of tornadic and nontornadic mesovortices. In addition, we also examined a QLCS case from February 2023 collected by a dual-polarization phased array radar known as the Advanced Technology Demonstrator to compare the impacts of radar update time and data quality on observing these precursor signatures.
An analysis of 145 mesovortices—92 tornadic and 53 nontornadic—reveals promising results for using some dual-polarization radar signatures to inform warning decisions regarding QLCS mesovortices. Statistically significant differences exist between the midlevel and low-level specific differential phase (KDP) cores of mesovortices with varying classifications of impacts (e.g., tornadic vs. nontornadic). In addition, the KDP core, especially at midlevels, frequently develops before the mesovortex does, so it could help forecasters anticipate mesovortex development before it occurs. Another near-surface signature known as a KDP drop was also present before nearly every mesovortex in this dataset and there appears to be a preferred location relative to this feature for mesovortex development, which could help forecasters anticipate where a mesovortex could develop. In contrast to the potential usefulness of KDP signatures, nearly no statistically significant differences existed between the differential reflectivity (ZDR) columns of tornadic and nontornadic mesovortices. In addition, we also examined a QLCS case from February 2023 collected by a dual-polarization phased array radar known as the Advanced Technology Demonstrator to compare the impacts of radar update time and data quality on observing these precursor signatures.
Supplementary URL: https://docs.google.com/presentation/d/e/2PACX-1vQF55DUmTu-AwpWcUOVjAq3qo6xqkvuMzHLu8xWsl5dRddsAcUE4qrTEndJ1HQ73rUykes9pPvFfv5d/pub?start=true&loop=false&delayms=60000&slide=id.p
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