Thunderstorm tracking in Northwest Europe for enhanced hazard preparedness

Abstract

The tracking of thunderstorms provides critical information on their frequency and behaviour for early warning, prediction and preparedness. Thunderstorm tracking has previously been constrained by the boundaries of a particular country or has focused on a particular category such as severe thunderstorms and mesoscale convective systems. However, less severe thunderstorms also pose a risk to life and property and occur more frequently and thus warrant inclusion in investigations of thunderstorm behaviour. In this paper, we present a new thunderstorm event catalogue, including all detected thunderstorms with at least three lightning flashes, derived from a tracking methodology applied to Northwest Europe within the bounds of 48° to 65°N and 15°W to 10°E between 2008 and 2018. The catalogue is based on ATDnet lightning flash data which was clustered into thunderstorms using a spatio‐temporal proximity assessment lightning clustering code written in the R coding language. The thunderstorm lightning clusters enabled the production of thunderstorm behaviour statistics such as speed, direction of movement, lightning flashes per minute and duration. This revealed that in winter, thunderstorms are shorter lived and move faster than in summer as well as more typically tracking from the west rather than from the south‐west. Thunderstorm behaviour characteristics were attributed to weather pattern types for the first time, providing probabilistic data that can be attributed to synoptic conditions. This can improve preparedness and early warning. Such results demonstrate how this new thunderstorm event catalogue, which includes all types and severities of thunderstorms unconstrained by political boundaries, can provide additional important information to enhance understanding of thunderstorm behaviour in the region. Our lightning clustering method may be useful for similar studies in other locales.

Region‐dependent meteorological conditions of thunderstorm based on clustering analysis of stability and precipitable water indices

“…We found that the correlation between summer climatological mean of surface wind speed and composite mean of K (PW) index during thunderstorms is statistically significant at −0.31 (−0.33). While thunderstorms are commonly associated with strong winds (Hayward et al, 2023), our finding further shows that areas characterized by lower values of K and PW indices during thunderstorms tend to exhibit higher surface wind speeds. Planetary boundary layer height (PBLH) affects the vertical distribution of temperature and moisture, which in turn influences CAPE available and moisture supply for thunderstorm development.…”

“…With the adoptions of improved observation methods and sophisticated mesoscale numerical models, the properties (e.g., flash rate, storm size, convective intensity, vertical structure, and microphysics) as well as dynamic and thermodynamic environmental conditions for thunderstorms are gradually revealed (Hayward et al, 2023; Islam et al, 2020; Kunz, 2007; Ma et al, 2021; Romps et al, 2014; Zhang et al, 2022). Several previous studies highlight the role of meteorological conditions and stability indices as the main reference for potential forecast of occurrence or non‐occurrence of thunderstorms in local areas.…”