Radiosonde observations of storm environments in Northern Greece

One of the main objectives of this study is to document and compare the atmospheric environments associated with hailstorms and non hail thunderstorms during the Greek National Hail Suppression Program (GNHSP) that protects an intensively cultivated area of Central Macedonia, Greece. The analysis focuses on identifying thresholds in various thermodynamic and kinematic parameters that might provide a good discrimination between these two environments based on radiosonde measurements. Convective Available Potential Energy (CAPE), lifted condensation level (LCL), wet bulb zero height, lapse rates, relative humidity, as well as vertical wind profile parameters (such as 0-6 km bulk shear) were derived from 06 UTC radiosondes that were held at Thessaloniki’s Airport Makedonia for the operational period between March and September of 2020-2024. Thermodynamic parameters on hailstorm days have higher median values than on non hail storm days, but there is considerable overlap between the distributions. The intramonthly variation of the thermodynamic parameters in the hailstorm environment shows that their values increase from spring to summer, while this does not apply for the kinematic parameters. Discriminating between hailstorm intensity categories, it is found that values of instability and moisture parameters, with some exceptions, are higher for the severe than for the non severe category, however there is again overlap between the distributions. Hail is most likely for high CAPE and this probability increases when bulk shear increases.