Weather Research and Forecast (WRF) Modeling System

1. Weather Research and Forecast (WRF) Modeling System Ü Develop an advanced mesoscale forecast and assimilation system Ü Promote closer ties between research and operations Context: Design for 1-10 km horizontal grids Advanced data assimilation and model physics Accurate and efficient across a broad range of scales Well-suited for both research and operations Community model support http://wrf-model.org

2. WRF Events for 2000+2001 12 January First WRF Oversight Board Meeting 29-30 March WRF Planning Workshop @ NCAR 23 June First Annual WRF Users Workshop First Meeting of WRF Science Board 30 November Release of “bare-bones” WRF Model 1-2 February WRF Planning Workshop @ NCEP WRF Status,updates and codes available from: wrf-model.org

3. WRFProject Management Steve Lord, Chair NOAA/NCEP Sandy MacDonald FSL & GFDL Bob Gall NCAR/MMM Steve Nelson NSF/ATM Col. Charles French USAF/AFWA Gloria Kulesa FAA WRF Oversight Board Joe Klemp NCAR/MMM WRF Coordinator WRF Science Board WRF Development Teams (5)

4. Morris Bender NOAA/OAR Stanley Benjamin NOAA/OAR Daewon Byun NOAA/ARL Mark DeMaria NOAA/NESDIS Jim Doyle NRL Jimy Dudhia NCAR Michael Farrar USAF/AFWA John Manobianco NASA/ENSCO Jeffrey McQueen NOAA/OAR Russell Schneider NOAA/NWS Nelson Seaman Penn State U. Danny Sims FAA/ACT-320 David Stensrud NOAA/OAR Wei-Kuo Tao NASA/GSFC Eric Thaler NOAA/NWS Greg Tripoli U. Wisconsin Robert Wilhelmson U. Illinois Ming Xue Oklahoma U./CAPS WRF Science Board

5. WRF Development Teams

6. Prototype Nonhydrostatic Model Solvers • Split-Explicit Eulerian Model: • Pressure and temperature diagnosed from thermodynamics • Two time level split-explicit time integration • Flux-form prognostic equations in terms of conserved variables • Accurate shape preserving advection • Both terrain-following height and mass coordinates being tested • Semi-Implicit Semi-Lagrangian Model: • Unstaggered (A) grid • Forward trajectories with cascade interpolation back to grid • High order compact differencing • Terrain following hybrid coordinate • Runge-Kutta (3rd & 4th order) time integration

7. Pre-implementation Strategy for WRF Model Testing at NCEP • GOAL I: perform clean, unambiguous comparisons between operational Meso and operational Meso using WRF design • Convert the existing highly efficient operational Meso Model code into the layered WRF modeling infrastructure • Immerses NCEP in layered WRF infrastructure • Tests will produce identical answers • Exercise selectable dynamics option in WRF • Use tested nonhydrostatic component of Meso • Future changes accelerated

8. Pre-implementation Strategy for WRF Model Testing at NCEP • Compare computer performance on current operational machine with current & future configurations (domain & resolution) • If a significant performance penalty is measured, then redesign may be called for • If no penalty is measured, then NCEP can immediately implement the layered WRF model design in operations for both nested & continental Meso runs making subsequent testing of replacement WRF components both clean and unambiguous

9. Pre-implementation Strategy for WRF Model Testing at NCEP GOAL II: perform clean, unambiguous comparisons between operational Meso and WRF prototypes • Compare forecast performance of WRF vs operations (hopefully both within WRF modeling infrastructure) • Emphasis on REAL-DATA retrospective case studies • Small and large-domain capabilities examined for nested and continental requirements of NCEP operations • Initial implementation expected in the small domain nested ‘Threats’ runs

10. Small 10 km Nested Meso Domains

11. Tests of Nonhydrostatic Nested Meso ModelCold Bubble Warm Bubble t t

12. Timeline for WRF Project Development Task 2000 2001 2002 2003 2004 2005-8 Basic WRF model (single dynamic core, limited physics, standard initialization) WRF model with selectable dynamic cores WRF model with hybrid vertical coordinate Research quality NWP version of WRF Basic Research suite Advanced suite Simple WRF model physics Advanced Basic Research 3-D VAR assimilation system Basic Advanced 4-D VAR assimilation system Testing for initial operational use at NCEP, AFWA and FSL Routine diagnosis of operational performance & of future refinements Release and support to community Implement into operations

13. Status of Initial Beta Release of Codes • Standard Initialization: Initial and lateral-boundary conditions extractable from real (Eta or AVN) and historical GRIB data • Documentation:WRF model design, programming standards, I/O application, standard intitialization package, physics, NetCDF output and basic ‘operating’ instructions • Model: terrain-following height version of Eulerian prototype - others will be tested in future

14. Status of Initial Beta Release of Codes • Codes downloadable from NCAR website (no extra community support resources available at NCAR at this time, so taking it out of hide) • “beta” version made available on 30 November 2000 • 113 registered downloads of the beta codes as of 1/29/01