Diurnal and Seasonal Variability of ERA5 Convective Parameters in Relation to Lightning Flash Rates in Poland

Abstract

The relationship between convective parameters derived from ERA5 and cloud-to-ground (CG) lightning flashes from the PERUN network in Poland was evaluated. All flashes detected between 2002–2019 were divided into intensity categories based on a peak 1-minute CG lightning flash rate and were collocated with proximal profiles from ERA5 to assess their climatological variability. Thunderstorms in Poland are the most frequent in July, between 1400–1600 UTC and over the southeastern parts of the country. The highest median of MUCAPE for CG lightning flash events is from June to August, between 1400–1600 UTC (around 900 J kg−1), whereas patterns in 0–6 km wind shear (DLS) are reversed, with the highest median values during winter and night (around 25 m s−1). The best overlap of MUCAPE and DLS (MUWMAXSHEAR parameter) is in July–August, typically between 1400–2000 UTC with median values of around 850 m2 s−2. Thunderstorms in Poland are the most frequent in MUCAPE below 1000 J kg−1, and DLS between 8–15 m s−1. Along with increasing MUCAPE and DLS, peak CG lightning flash rates increase as well. Compared to DLS, MUCAPE is a more important parameter in forecasting any lightning activity, but when these two are combined together (MUWMAXSHEAR) they are more reliable in distinguishing between thunderstorms producing small and high CG lightning flash rates. Our results also indicate that higher CG lightning flash rates result in thunderstorms more frequently associated with severe weather reports (hail, tornado, wind).

Major Role of Marine Heatwave and Anthropogenic Climate Change on a Giant Hail Event in Spain

“…(2022) and Poręba et al. (2022). Furthermore, an additional condition is added using the ERA5 hourly convective precipitation rate (>0.25 mm/hr) as a proxy for convective initiation (Taszarek, Allen, Brooks, et al., 2021; Taszarek, Allen, Groenemeijer, et al., 2020; Taszarek, Allen, Marchio, & Brooks, 2021; Taszarek, Allen, Púčik, et al., 2020).…”

“…This proxy consists of a 5 cm threshold for the Hail Size Index (HSI; Czernecki et al, 2019). HSI was previously applied in Papavasileiou et al (2022) and Poręba et al (2022). Furthermore, an additional condition is added using the ERA5 hourly convective precipitation rate (>0.25 mm/hr) as a proxy for convective initiation Taszarek, Allen, Groenemeijer, et al, 2020;Taszarek, Allen, Marchio, & Brooks, 2021;Taszarek, Allen, Púčik, et al, 2020).…”

Comparison of thunderstorm days in Poland based on SYNOP reports and PERUN lightning detection system

“…According to Kolendowicz (2006), the season of maximum thunder activity lasts from May 16 to August 13 on the Baltic Sea coast and until August 18 in the rest of the country. In May and the summer months, the thermodynamic instability of the atmosphere increases, favouring convective movements and the development of cumulonimbus clouds (Poręba et al 2022). In the autumn (September-October) the frequency of TDs decreases sharply, but there is high frequency of thunderstorms along the Baltic coast.…”

Forecasting Large Hail and Lightning using Additive Logistic Regression Models and the ECMWF Reforecasts

“…While moderate buoyancy (CAPE > 1000 𝐽𝑘𝑔 −1 ) was present in both regions, the main difference in the two profiles was the mid-level relative humidity, significantly lower in the Italian sounding. Here a deep, dry layer in the midtroposphere could have resulted in dry air entrainment of updrafts that inhibited convective initiation (Rädler et al 2019, Poręba et al 2022). The comparison between hail and lightning forecasts highlights the model's ability to distinguish between regions with lightning potential and with hail potential.…”