In this paper, a synoptic and mesoscale analysis of five selected hail cases in the Gulf of Trieste and Istria during the period 2010-2014 was performed. The analysis was made with the aim of better understanding the causes of increased (early)morning convective activity. The type of synoptic conditions was subjectively assessed based on synoptic maps and profiles of radiosonde measurements at 12:00 and 00:00 UTC from Udine station. In the analysis of each case, using the mesoscale numerical model WRF, attempts were made to reproduce the conditions conducive to the development of convection and the occurrence of hail. The modeled fields were compared with data collected at 34 meteorological/climatological stations irregularly distributed in Istria. A comparison of hail parameters obtained by special measurements from the hail meter network with the results of the WRF-HAILCAST model was performed, as well as a comparison of measured lightning strikes from the LINET network with the predicted potential for lightning development from the WRF model. Comparisons conducted on five selected cases gave satisfactory results and indicated the usefulness of applying these algorithms. Numerical simulations gave further insight into the spatial-temporal characteristics of convection in the northern Adriatic and distinguished various contributions of synoptic and mesoscale processes. In three analyzed cases, the synoptic flow over Istria prevented a significant development of the thermally-generated flow of smaller mesoscale dimensions. Yet, in two cases, the thermally-generated wind of a smaller scale was superimposed on the synoptic wind of a larger scale and thus influenced the development of convection. The main consequence was the creation of several significant zones of convergence in the field of currents above sea level due to (i) generation of airflow coming from land to sea and (ii) modifications of currents from south to southeast due to the shape and height of the coast over the Istrian peninsula. The resulting ground convergence of the wind facilitated the formation/maintenance of convective cells.