1 National Meteorological Administration, Bacău Regional Forecast Center, 3 Timpului Street, 600234,
Bacău, Romania 2 “Vasile Alecsandri” National College, 37 Vasile Alecsandri Street, 600011, Bacău, Romania
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.