1. Hurricane forecasts with Regional NMMB: Impact of HWRF Physics Weiguo Wang and Vijay Tallapragada EMC/NCEP/NOAA, College Park, MD 20740 Mar. 2015 1

2. Outline Importance of physics in Hurricane forecast HWRF physics packages into NMMB Hurricane simulations with regional NMMB + NMMB with ‘NAM physics’ vs with ‘HWRF physics’ + NMMB with ‘HWRF phys’ vs operational HWRF Summary and Future work 2

3. Introduction + The Nonhydrostatic Multi-Scale Model on B grid (NMMB) is the second generation of nonhydrostatic models developed at NCEP. It performs well, and replaced WRF-NMM (HWRF’s dynamic core) years ago in NAM. + NMMB has the potential to continue to advance our hurricane forecast capability, given good parameterizations of hurricane physics. + Storm intensity and track are sensitive to the parameterizations of physical processes such as PBL, convection, microphysics, radiation, even land surface exchange + HWRF physics package has been well tested, and performed well to simulate hurricane structure in addition to intensity and track. 3

4. HWRF physics to NMMB Following physics schemes used in operational HWRF have been added to NMMB: 1.GFSPBL scheme 2.GFDL surface layer plus GFDL land surface scheme 3.SAS scheme 4.MESO-SAS scheme 5.Add empirical z 0 for hurricane to MYJ surface scheme NMMB has “fer”, “fer_high” micophysics schemes, and “gfdl”, “rrtmg” for radiation; those are very similar to HWRF’s. 4

5. How to use - Options in configure files # turbulence: gfspblhur convection: sashur sfc_layer: gfdl land_surface: gfdlslab - Tunable variables can be changed in configure files, default values are those currently-used in HWRF # RUN_TC=.true. ! true='run hurricane' sas_pgconvar_ric sas_shal_pgconcoef_ric_l shallow_convcoef_ric_s sas_shalconvALPHA sas_mass_fluxSFENTH sas_mommixDISHEAT 5

6. Operational HWRF vortex Initial conditions GFS 0.5-degree data Boundary Conditions NPS NMMB configure_file_d01 namelist.nps Post/Tracker Graphics Can be replaced by spectral data Will be replaced by NMMB-DA/INIT Flow chart for tests 6

7. Configuration 01 “Hwrfphys” turbulence: gfshur sfc_layer: gfdl land_surface: gfdlslab convection: sashur microphysics: fer shortwave: gfdl longwave: gfdl Configuration 02 “NAM-like” turbulence: myj sfc_layer: myj land_surface: noah convection: bmj microphysics: fer shortwave: gfdl longwave: gfdl NMMB Hurricane simulations 27-9-3 domains, 43-level, feedback=0.5 No ocean, no DA 7

8. ARTHUR simulated by regional NMMB with HWRF phys 8

9. HWRF phys NAM phys 9

10. 36 hr, near landing 10m wind E-W cross section NAM physHWRF phys 10

11. Compare NMMB using HWRF phys with Operational HWRF NMMB (red) Intensity very close to HWRF (purple), and even better timing of max 11

12. Another NMMB run: turbulence: gfspbl sfc_layer: myj ( z 0 modification ) land_surface: noah Comparison of myj/noah- LSM and GFDL/slab from NMMB runs. 12

13. Summary 13 With HWRF phys package, regional NMMB can well simulate hurricane structure, intensity and track, showing potential to further advance NCEP capability to hurricane forecast. Comparison with physics options in NAM shows importance of using good physics parameterizations for hurricanes. Future work: improve nest motion algorithm, other components (e.g., DA + init) from HWRF system, …