Assessment of spatial and temporal dynamics and forecasting of convective phenomena in Belarus

Due to climate change in recent decades the frequency of weather events caused by the development of convective processes has increased in Belarus. As a result of their activation in the warm period of the year powerful convective clouds are formed. Heavy rainfall, hail, thunderstorms, squalls and tornadoes are a complex of the most dangerous weather events associated with strong convective clouds. We used data from weather stations of the hydrometeorological network in Belarus during the warm periods (April-October) of 1994-2023. It was revealed that 439 convective phenomena (CP) were observed during the study period. Very heavy rain was most often observed – 291 cases (66%), very heavy rain - less frequently (36 cases, or 8%). Very strong winds (including squalls) were observed in 85 cases (20%) and large hail - in 27 cases. 83% of all CP were observed in the summer, 10% in the spring and 7% in the autumn. The largest number of CP was observed in July. The maximum frequency of CP was recorded in the south and south-east of Belarus. Due to the fact that these areas are most susceptible to the influence of warm unstable air masses coming from the south into the country. In the northern regions of the republic, a high number of CP was associated with the influence of Atlantic cyclones and their atmospheric fronts. The forecast of the degree of atmospheric instability plays a key role in forecasting convective phenomena. We analyzed the statistical relationships between the instability indices obtained from ERA5 reanalysis, the types of CP and the synoptic situation. It has been revealed that the combined use of several indices describing different aspects of convection (energetic CAPE, stratification LI, complex SWEAT) gives the best result in predicting CP.