Proximity Soundings of Severe and Nonsevere Thunderstorms in Central Europe

Abstract

18The environments of severe and non-severe thunderstorms were analysed using 16 421 19 proximity soundings from December 2007 to December 2013 taken at 32 Central European 20 stations. The soundings were assigned severity categories for the hazards hail, wind, tornado 21 and rain. For each of the soundings, parameters were calculated representing the instability, 22 vertical wind profile and moisture of the environment. The probability of the various hazards 23 as a function of CAPE and 0-6 km bulk shear (DLS) is quite different for each of the hazards.24Large hail is most likely for high CAPE and high DLS, a regime that also supports severe 25 wind events. A second severe wind regime exists for low CAPE and very high DLS. These 26 events are mostly cold season events. Storms with significant tornadoes occur with much 27 higher DLS than storms with weak or no tornadoes, but with similar CAPE. 0-1 km bulk 28 shear (LLS) does not discriminate better than DLS between weak and significant tornadoes. 29Heavy rain events occur across a wide range of DLS, but with CAPE above the median for 30 non-severe thunderstorms and are most likely when both absolute humidity in the boundary 31 layer and relative humidity in the low-to mid-troposphere are high. LCL height does not 32 discriminate well between the intensity categories of tornadoes, but higher LCL heights were 33 associated with higher probability of severe hail. Storm relative helicity shows similar results 34 to DLS, but with more overlap among intensity categories. 35 36 37

Characterizing severe weather potential in synoptically weakly forced thunderstorm environments

“…This same conceptual model has been promoted by previous severe convective wind research (e.g., Atkins and Wakimoto, 1991;Kingsmill and Wakimoto, 1991;Wolfson, 1988). The results of SHS days also support previous findings (Johns and Doswell, 1992;Moore and Pino, 1990;Púčik et al, 2015). The distributions in Fig.…”

Future Changes in European Severe Convection Environments in a Regional Climate Model Ensemble

“…We ensured that the selected layer was always above the local topography (surface) by preventing layers below the topography from being selected. To show how LI is related to CAPE values, we use a database of soundings from Pú cik et al (2015) that contains 16 000 thunderstorm proximity soundings for central Europe. For these soundings, LI values decrease with increasing CAPE, although there is considerable scatter in CAPE values for a particular value of LI (Fig.…”

“…The presence of sizable CAPE ensures that convective updrafts, once initiated, can become strong, whereas the vertical wind shear promotes storm organization and longevity and potentially amplifies the updraft (Weisman and Klemp 1982). The notion that the probability of convective hazards universally is a function of latent instability and DLS is supported by (pseudo)radiosonde studies in the United States (Brooks , 2013, Europe (Groenemeijer and van Delden 2007;Brooks 2013;Pú cik et al 2015), and Australia (Allen and Karoly 2014).…”

“…The relationship between severe storm hazards and the large-scale environment is far more complex than can be inferred from latent instability and deep layer shear. For most of the hazards, other factors are important as well, such as the lower tropospheric shear and humidity for tornadoes (Thompson et al 2003) or the lifted condensation level (Pú cik et al 2015) or freezing level (Dessens et al 2015) for hail.…”

The Hamburg Tornado (7 June 2016) from the perspective of low-cost high-resolution radar data and weather forecast model

“…Based on proximity soundings or numerical weather prediction output, environments favorable for tornadoes were identified and multiple indices developed (e.g. Craven and Brooks, 2004;Thompson et al, 2003Thompson et al, , 2012Púčik et al, 2015).…”