Modeling Group Onvlee, Dudhia, Auger, Cober, Lean, Alexander, Milbrandt, Steiner, Brown

Questions Identify specific development/improvement efforts that the NWP community can make to improve the performance of NWP in the nowcasting range New ideas and techniques to improve/optimize the direct/indirect use of NWP for nowcasting. Suggestions for international collaboration in experimentation concerning the NWP use in nowcasting

Not just convection: stable BL Identify specific development/improvement efforts that the NWP community can make to improve the performance of NWP in the nowcasting range Not just convection: stable BL Sensitivity to PBL schemes as much asmicrophysics PBL depth, water vapor, vertical structure, grey zone (< 1 km) Surface initialization: snow, physiographic data, complex terrain resolution Downscaling/post-processing products (terrain, fog) Verifying PBL/turbulence in grey zone

Short-range physics effects? PBL development of turbulence Microphysics, aerosol, double-moment, tuning Shallow cumulus even at cloud-permitting scale (cloud-top PBL) High-frequency radiation calls (for cloud motion) Cloud initialization uncertainty Surface uncertainty (hi-res analysis can be used)

Education and training in use of models datasets at high resolution Use of ensembles (deterministic v ensemble resolution) in nowcasting – how? Uncertainties (analysis, LBC, model physics, cloud analysis, surface) Education and training in use of models datasets at high resolution Next generation of computers changes physics problems to be addressed

Field programs (PBL, shallow cu, precipitation, process understanding) Suggestions for international collaboration in experimentation concerning the NWP use in nowcasting Field programs (PBL, shallow cu, precipitation, process understanding) Modelers need to be involved (FDPs, RDPs) Shallow cumulus Convective initiation (UK, Canada) HYMEX (hydrology cycle) FROST14 (winter weather, Russia)