A Study of the 23 October 2022 Southern England Damaging MCS

"Cool-season convective storms over northwestern Europe and Great Britain continue to be a forecasting challenge as well as a public safety hazard, especially during periods of unseasonably warm temperatures and associated enhanced instability. Among the most common cool-season storms are the mesoscale convective system (MCS), defined as a deep convective system that is considerably larger than an individual thunderstorm and that is often marked by an extensive middle to upper tropospheric stratiform-anvil cloud of several hundred kilometers in horizontal dimension. The physical structure of an MCS promotes the generation of strong and potentially damaging straight-line winds resulting from gust fronts and convective downbursts that arise from mid-level storm inflow and subsequent cold-pool generation. During the afternoon of 23 October 2022, an MCS developed and intensified over the English Channel and tracked north-northeastward into southern England, producing widespread damaging winds and at least three moderate to strong tornadoes in Hampshire. In general, atmospheric temperature and moisture profiles from NOAA satellites and numerical models indicated a high potential for severe thunderstorm, straight line wind, and tornado occurrence over southern England. Radar and satellite observed coincidently high rain rates and very low storm-top temperatures as well as prominent trends in MCS organization and intensity that suggested damaging outflow wind. In addition, convective-scale models (both UM and WRF) provided good representation of the event allowing the most relevant physical processes to be examined further.