Motion characteristics of thunderstorms in southern Germany

The motion of thunderstorms in southern Germany was investigated. The thunderstorms were observed by a lightning position system during the summer months of the years 1992–1996. On average every second day thunderstorms were observed somewhere in southern Germany. In general thunderstorms approached from westerly and south-westerly directions. The average speed was 13 m s−1. No significant relation between the occurrence of thunderstorms and the large-scale synoptic pattern described by the Grosswetterlagen (large-scale weather pattern) was found. Thunderstorms were observed during almost all Grosswetterlagen. The reduction to eight weather patterns based on the low-level flow in southern Germany showed that thunderstorms are likely when the flow has a westerly (43%) or easterly direction (20%). Three distinct groups of different lighting patterns could be identified: stationary, moving thunderstorms and thunderstorm lines. The convective available potential energy (CAPE) and the wind shear were retrieved from radio soundings from Munchen and Stuttgart. On average CAPE was 583 J kg−1 for stationary thunderstorms, 701 J kg−1 for moving thunderstorms and 876 J kg−1 for thunderstorm lines. The corresponding average bulk Richardson numbers were 37, 22 and 21. The steering level was found to be at about 6 km m.s.l. However, it should be noted that in most cases the soundings do not completely describe the local environment of thunderstorms, since radio soundings are only available twice a day. Copyright © 1999 Royal Meteorological Society

[1]  Alan R. Moller,et al.  The Operational Recognition of Supercell Thunderstorm Environments and Storm Structures , 1994 .

[2]  R. Stull An Introduction to Boundary Layer Meteorology , 1988 .

[3]  Joseph B. Klemp,et al.  The structure and classification of numerically simulated convective storms in directionally varying wind shears , 1984 .

[4]  D. Heimann,et al.  A Squall Line in Southern Germany: Kinematics and Precipitation Formation as Deduced by Advanced Polarimetric and Doppler Radar Measurements , 1991 .

[5]  W. Schmid,et al.  Hailstorms in Switzerland: Left Movers, Right Movers, and False Hooks , 1993 .

[6]  E. Hoffmann,et al.  Ein Blitzortungssystem für die Elektrizitätsversorgung , 1991 .

[7]  H. Huntrieser,et al.  Comparison of Traditional and Newly Developed Thunderstorm Indices for Switzerland , 1997 .

[8]  Joseph B. Klemp,et al.  The Dependence of Numerically Simulated Convective Storms on Vertical Wind Shear and Buoyancy , 1982 .

[9]  T. Hauf,et al.  The Characteristics of Lightning Occurrence in Southern Germany , 1996 .

[10]  John Hubbert,et al.  Life Cycle and Precipitation Formation in a Hybrid-Type Hailstorm Revealed by Polarimetric and Doppler Radar Measurements , 1994 .

[11]  H. Höller Mesoscale organization and hailfall characteristics of deep convection in southern Germany , 1994 .

[12]  Robert A. Houze,et al.  Mesoscale Organization of Springtime Rainstorms in Oklahoma , 1990 .

[13]  H. Huntrieser,et al.  The Mesoscale Structure of Severe Precipitation Systems in Switzerland , 1995 .