PREDICTIVE CAPABILITIES OF A ONE-DIMENSIONAL CONVECTIVE CLOUD MODEL WITH FORCED LIFTING AND A NEW ENTRAINMENT FORMULATION

A one-dimensional time-dependent nonhydrostatic convective cloud model , with an entrainment formulation that includes the combined effects o f turbulent and organized dynamic processes and forced lifting, is use d to improve the forecasting of maximum cloud-top heights for applicat ion in the hail suppression program of the Hydrometeorological Service of Serbia. The model is focused on the comparison between simulated a nd observed cloud-top heights for 50 nocturnal thunderstorms, using fo ur different entrainment rates. It is shown that the model results are highly dependent on the entrainment formulation used. The correlation coefficient r between predicted cloud-top heights and radar echo tops varies from 0.48 to 0.90 depending on the entrainment rate. The most acceptable model results are obtained for the entrainment rate that do minates the dynamic process (r = 0.89). The forced lifting slightly in creases the correlation coefficient (r = 0.90) since it tends to impro ve predicted cloud tops with heights between 8.5 and 11 km.