In this study, the WRF-HAILCAST model was used with focus on analyzing the cases of early morning hail in the south Adriatic. This area is specific for the fact that hailstorm occur more often in the winter period, but with no afternoon maximum in the diurnal course like it appears for the hailstorms over the continent. Contrary, the early morning maximum stands out in the colder part of the year. Mechanisms that lead to convection are then different than the ones in the continent and more investigation is needed to find the causes of convection in these conditions. The goal of this study is to carry out numerical simulations for a select few cases of winter convection in the southern Adriatic and evaluate the success of the model in simulating hail and the selected meteorological parameters. For this analysis, the study uses synoptic charts and radiosounding profiles from station Zadar - Zemunik. The obtained results where then compared to the measured data from the Croatian Meteorological and Hydrological Service’s network of surface stations. Moreover, the calculated potential of lightning activity (LPI) was compared to the measured data of lightning activity from the LINET network and the study carries out the scale decomposition of the wind flow field using the Barnes filter to obtain better information on the effect of the individual scales in the total wind flow field. The results show that the model underestimates the size of the hail, but overestimates the spatial distribution of the simulated hail. Also, the model predicts the temperature and air pressure data very well, but it shows poor results in predicting the relative humidity data. Despite that, the model gave good results and it successfully simulated the meteorological conditions that led to the development of convection and hail in all observed cases.