JMA has experimentally operated the mesoscale ensemble prediction system (MEPS) with 11 members and the same configurations as the MSM to support in preparing warnings and information for disaster prevention and to provide information for the next generation air traffic control system in Japan. To achieve the purpose, we developed ensemble-based forecast indices of turbulence, icing, and CB-cloud amount and height using the MEPS. Basically those indices are calculated simply from each ensemble member. The results of verification showed that the ensemble-based indices improve forecast accuracy significantly over that observed with the original indices based on the MSM. This presentation will include the outline of the ensemble-based indices, the results of verification, and some case studies.