Warunki synoptyczne sprzyjające rozwojowi burz nocnych w Polsce = Synoptic conditions favouring the development of nocturnal thunderstorms in Poland

Abstract

This article presents research into the meteorological conditions underpinning the development of night thunderstorms in Poland. The main objective was thus to identify the synoptic situations favouring nocturnal thunderstorms, as well as to determine which convection indices are of greatest relevance to forecasts of this type of thunderstorm. The research detailed here was carried out by analysing cloud-to-ground lightning flashes registered in Poland in the years 2002‑2018 via the PERUN system. ERA 5 reanalysis was used to obtain relevant atmospheric parameters and convection indices. In addition, synoptic analysis was carried out for specified thunderstorms, with their dominant structure also determined. No fewer than 1.5 million cloud-to-ground lightning flashes were analysed for the purposes of this study. These data making it clear that the development of nocturnal thunderstorms is favoured primarily in conditions of a waving front, cold front or wind convergence line. In all cases, the jet stream in the upper troposphere emerged as an additional factor increasing the development and activity of nocturnal thunderstorms.