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What is the “NAM”?

What is the “NAM”?. David Novak Science and Operations Officer NOAA/NCEP/ Hydrometeorological Prediction Center. Motivation. How to make sense of a blizzard of acronyms referring to: Native model differences Display resolution differences NMAP naming conventions. The NAM.

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What is the “NAM”?

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  1. What is the “NAM”? David Novak Science and Operations Officer NOAA/NCEP/ Hydrometeorological Prediction Center

  2. Motivation • How to make sense of a blizzard of acronyms referring to: • Native model differences • Display resolution differences • NMAP naming conventions

  3. The NAM NAM = North American Mesoscale Model EMC/NCO consider it the name of a computing slot on the supercomputer. The core model can change, the model physics can change, the resolution can change, and it will still be called the “NAM” The core model recently changed from the WRF-NMM to the NMMB in October, 2011.

  4. Native Model Differences “Parent” domain -12 km native resolution -Large North American domain -Uses full convective parameterization -Boundary conditions from GFS 12 km 6 km Alaska Fixed Nests -High Resolution -6 km Alaska -4 km CONUS -2.5 km OCONUS domains -Boundary conditions from parent NAM domain **Limited or no convective parameterization 4 km CONUS 2.5 km 1.3 km 2.5 km Hawaii Peurto Rico Fire Weather Nest -Moveable 1.33 km nest -Boundary Condtions from fixed nest

  5. NMAP Names “Parent” domain nam12 12 km 6 km CONUS Nest nam_conest Alaska 4 km CONUS Puerto Rico Nest nam_prnest 2.5 km 1.3 km 2.5 km Fire Weather Nest nam_firewx Hawaii Peurto Rico

  6. nam12 30 h forecast 6-h accumulated precipitation valid 18 UTC 29 October 2011

  7. nam_conest • More detail • Differences in intense precipitation areas 30 h forecast 6-h accumulated precipitation valid 18 UTC 29 October 2011

  8. nam_firewx • Downscaling of the nest 30 h forecast 6-h accumulated precipitation valid 18 UTC 29 October 2011

  9. RFC Stage IV QPE 6-h accumulated precipitation ending 18 UTC 29 October 2011

  10. nam12 24 h forecast 24-h accumulated precipitation valid 12 UTC 9 Nov 2011

  11. Nam_conest 24 h forecast 24-h accumulated precipitation valid 12 UTC 9 Nov 2011

  12. RFC Stage IV QPE 24-h accumulated precipitation ending 12 UTC 9 November 2011

  13. Native Model Differences Summary • nam12 and nam_conest can be quite different for precipitation • -Likely mostly due to the limited use of convective parameterization on the 4 km nest and the higher resolution. • Smaller differences in mass fields (heights, temps, etc) • FireWx Nest is mostly a downscaling of the 4 km CONUS Nest

  14. Display Resolution Differences • NCO provides NAM data with variety of domains/resolutions.

  15. 80 km

  16. 40 km

  17. 12 km

  18. 4 km CONUS Nest

  19. NSSL QPE

  20. Can we Simplify this? • NCO / OPC/ HPC in discussions

  21. HiResWindow Runs ≠ CONUS Nest • Different model cores (WRF-NMM/ WRF-ARW vs. NMMB) • Smaller domains • Arrive later in the cycle • Forecasts only to 48 h • Can be preempted by hurricane runs 18Z 06Z, 18Z 00Z, 12Z 00Z 12Z 06Z

  22. Summary Know what you are looking at • Native model differences • Display resolution differences • NMAP naming conventions Are your spf’s updated? -Take advantage of new data Questions, feedback, & ideas welcome!

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