Research will be focused on the meteorological processes that influence the predictability of High Impact Weather: control of convective scale predictability by large scale processes in tropical & extra-tropical latitudes; differences in predictability of hazardous weather relative to “normal” weather; association with forecasts that are very sensitive to initial state; mechanisms that produce quasistationary hazardous weather systems; role of diabatic heating; role of boundary layer and land surface; pre-conditioning of the land surface for hazards. These research challenges will be addressed through the use of datasets from recent and planned field experiments, especially the planned North Atlantic waveguide experiment, NAWDEX/DOWNSTREAM, Lake Victoria experiment, LVB-HyNEWS, and La Plata basin experiment, ALERT.AR/RELAMPAGO, through co-ordinated case studies and model inter-comparisons, and in review papers and targeted workshops.