Synoptic and Mesoscale Conditions Generating High Amounts of Precipitation in June 2020, In Romania

The first part of the study analyzes the precipitations recorded in June over the 1961-2020 period for 22 climatological weather stations over different regions of Romania in order to determine if precipitations in June 2020 were higher than those recorded before 2020. For this, 5 precipitation indices have been used: number of heavy and very heavy precipitation days, 24-, 48- and 72-hours precipitation amounts. The second part is dedicated to precipitations recorded in June 2020, registered at 157 weather stations from Romania, divided in historical regions; it analyzes the number of heavy and very heavy precipitation days, synoptic and mesoscale conditions from different periods of time using the specific methods of investigation (charts of sea level pressure, geopotential height, temperature and humidity, atmospheric soundings, different stability indices, vertical wind shear, infrared and visible satellite images and radar images of convective storms). The main findings are: precipitations recorded in June 2020 at 22 climatological weather stations did not exceed the absolute maximum precipitation recorded between 1961-2019, and precipitations recorded in 24, 48 and 72 hours were higher only at 2 or 3 weather stations; the number of heavy and very heavy precipitation days recorded in June 2020 were higher in the Carpathians, the North and Center, and the West regions of Romania; synoptic conditions were determined by low values of atmospheric pressure at the surface and/or by the atmospheric depressions, while in the middle troposphere, an atmospheric trough or a cut-off low was present; mesoscale conditions presented low or medium values of Convective Available Potential Energy, negative values of Lifted Index, and weak or medium wind shear in the 0-3 km layer.