MRB and CMC from now on will put some emphasis on the prediction of extreme weather events trough the Canadian Weather Research Project (CWRP). In view of this objective, we have pursued an effort in mesoscale modeling and diagnostics. In our non-hydrostatic mesoscale modeling effort, the treatment of the lateral BCs in our research limited-area non-hydrostatic model MC2 (Benoit et al., 1997) has been fully revised to implement truly open conditions. Optimization of the scheme for a multi-processor environment has been made, resulting in a fully vectorized version of the scheme that allows MC2 to run at full speed (e.g. ~ 800 MFlop/PE) (Thomas et al., 1997,1998). Field projects have been again supported or prepared this year using MC2, like FIRE-ACE (Arctic Cloud Experiment) and the Mesoscale Alpine Programme (MAP). Work has begun to develop a truly limited-area version of the RPN-CMC GEM operational model. A prototype GEM-LAM should be completed by 2000. We have also made a study of inertia-gravity wave generation, propagation, transience and breaking over the Rockies, the North Pacific and Central America in the troposphere-stratosphere-mesosphere GFDL SKYHI general circulation model (Charron and Brunet, 1999).