Severe weather events in Moldavia region, on June 23, 2019

Diana-Corina BOSTAN, Adrian TIMOFTE, Sorin BOSTAN


The forecast of torrential rainfall is quite laborious and sometimes difficult. The difficulty lies in estimating the quantitative threshold and the spatial distribution of rainfall. Such a study is necessary because it has been found that in the last 30-40 years, the severity of convective phenomena has increased. Through such studies, it is desired to improve the short and very short-term weather forecasts, so that the population and the authorities can limit, as much as possible, the damage in the field. In operational meteorology we constantly work with the concepts of isobars, isohypses, isohyets. In our study, we used another meteorological parameter, less used in the operative routine (in addition to those commonly used) - the equipotential temperature, respectively the map of vertical section with the distribution of isentropes, to analyze severe meteorological phenomena, which took place in the Moldavia region. Forecasts are easy when forecast models are heading in the same direction. But, things get complicated when the atmospheric instability is much more severe than initially anticipated and the phenomena are in full development. The solution to this is found in the fact that the forecasting activity also has a special segment - very short-term forecasts, namely nowcasting forecast (which is based on the interpretation of radar imaging). In this paper, such an example is presented. Due to minor changes in the air circulation in the lower troposphere, the convective phenomena were much more severe than those anticipated by the forecast models. On June 23, 2019, 23 immediate warning messages were issued until midnight, regarding torrential rains, storms and hail. From those issued, 21 were orange code warnings and 2 were red code warnings. In this way, the authorities intervened in due time, so that the losses in the field were minimized as much as possible.

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