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HPC Medium Range Grid Improvements

HPC Medium Range Grid Improvements. Mike Schichtel, Chris Bailey, Keith Brill, and David Novak. Medium Range Desk. Temps/PoP. Pressure/Fronts. Staffed 1030-1930 UTC by two forecasters -Temperatures/Pop Desk Max/MinT and PoP Grids -Pressure/Fronts Desk Winds Grids.

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HPC Medium Range Grid Improvements

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  1. HPC Medium Range Grid Improvements Mike Schichtel, Chris Bailey, Keith Brill, and David Novak

  2. Medium Range Desk Temps/PoP Pressure/Fronts • Staffed 1030-1930 UTC by two forecasters • -Temperatures/Pop Desk • Max/MinT and PoP Grids • -Pressure/Fronts Desk • Winds Grids • Sky, Dewpoint, and Wx derived • Preliminary grids issued by 1415 UTC (15 UTC deadline) • -including 00 UTC ECMWF ensemble • Final grids usually issued by 18 UTC (20 UTC deadline) • -incorporating 12 UTC guidance suite without ECMWF

  3. HPCGuide Medium Range 5 km Grids MIN TEMPS MAX TEMPS WINDS 12 HOUR POPS DEWPOINTS CLOUD COVER WEATHER TYPE

  4. Day 7 Skill 2008 = Day 5 Skill 2001! _ _ _ _ _ _ _ _

  5. Anomaly correlation die-off scores of Model and Ensemble Mean Forecasts

  6. Primary Medium Range Models/Ensembles at HPC Total: 288 individual runs per day!

  7. Medium Range Data GEFS Member ECMWF Member Full International Guidance Suite including ECMWF deterministic and ensemble and bias-corrected NAEFS 90 Ensemble members CMC Member ECMWF Mean NAEFS Mean GEFS Mean GFS ECMWF

  8. Forecast Process • Forecaster compares an international guidance suite, GFS MOS, climatology, and HPC and NDFD (NWS) continuity • Forecaster chooses blends and weights Maximum Temps vs. GFS MOS HPC Continuity NDFD Continuity ECMWF Ens Blender Final Product GFS ECMWF MSC DGEX ICT HPC

  9. Improvements MadeTd and Sky • April 15, 2010: Methods to derive Dew Point and Sky Changed. MAE improved up to 20%. • Dew Point: Model guidance weighted according to forecaster’s Max/MinT blends. Downscaled by using a GDAS-RTMA difference accumulated by applying a decaying weight through time. • Sky: Model guidance weighted according to forecaster’s PoP blends. No downscaling. Better in Cool Season Testing Feb 2010 (green = new) Testing June 09 – Jan 2010 (green = new)

  10. Improvements MadeTd Comparison Before • MDL Verification Comparison of April-Sept (00 UTC cycle) HPC (green) highest medium range MAE

  11. Improvements MadeTd Comparison After Change • MDL Verification Comparison April-Sept (00 UTC cycle) HPC (green) now lowest MAE Given longer history verification shown in slide #9, HPC skill should be better during cool season

  12. Latest Improvements Operational as of November 2: Increased use of model guidance downscaled using RTMA instead of PRISM. New Day 7 skill equals = Old method Day 5.5 _ _ _ _ _ _ _ _ This new HPC DS_FNL score does not yet reflect additional benefits from bias corrections and forecaster modifications

  13. New Day 7 skill equals = Old method Day 5.5 _ _ _ _ _ _ _ _ _ This new HPC DS_FNL score does not yet reflect additional benefits from bias corrections and forecaster modifications

  14. Other Elements Wind Speed HPC similar to NDFD Jul ‘09 – Jul ‘10

  15. Other Elements 12 h PoP HPC better than MOS and similar to NDFD Jul ‘09 – Jul ‘10

  16. Improvements Prototyped6 hFloating Pop • 6 h statistical PoPs generated from international model suite • The 6 h period with the higher PoP is set to the HPC 12 h PoP (consistent with floating PoP principles) • The remaining 6 h period is assigned the statistical 6 h PoP value • Renamed “Precipitation Likelihood Index” to avoid public confusion. • Real-time prototyped images available at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody_newparms.html • Which can be compared to the operational suite at:http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html

  17. Improvements PrototypedWeather Grid Enhancements • Time resolution increased from 12 h to 6 hourly • Precipitation Type Algorithm improved (top-down approach) • Slight chance, chance, and likely qualifiers added (based on HPC PoP) • Real-time prototyped images available at: http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody_newparms.html • Which can be compared to the operational suite at:http://www.hpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html

  18. Collaboration Academia / Publications Conferences (like NROW) CSTAR Rossby Wave Packets etc. EMC / THORPEX Adaptive Observations Targeting Observation Program WFOs/RFCs 12Planet Chatroom and coordination calls

  19. Summary • HPC uses full suite of international model guidance • Given limited forecaster resources, increasingly relying on forecaster blending input coupled with post processing • Improvements to Td and Sky have been made • Improvements to PoP and Wx grids prototyped • Improvements to Max/MinTemps November 2010 (now!) • Open to suggestions • for improvement

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