1. Translating Advances in Numerical Weather Prediction into Official NWS Forecasts David P. Ruth Meteorological Development Laboratory Symposium on the 50 th Anniversary of Operational NWP June 17, 2004

2. Symposium 50 th Anniversary Operational NWP Coming of the Digital Age for Official NWS Forecasts Operational Numerical ModelsOperational Numerical Models Model Output Statistics (MOS)Model Output Statistics (MOS) Interactive Forecast Preparation System (IFPS)Interactive Forecast Preparation System (IFPS)

3. Symposium 50 th Anniversary Operational NWP Benefits of Interactive Forecast Preparation Maximizes human contribution to forecast processMaximizes human contribution to forecast process Provides more forecast detail in time and spaceProvides more forecast detail in time and space Enables more effective communication with users (e.g., graphics)Enables more effective communication with users (e.g., graphics) Increases the usefulness of NWS forecasts to customers and partnersIncreases the usefulness of NWS forecasts to customers and partners

4. Symposium 50 th Anniversary Operational NWP How does IFPS work? A 7-day digital forecast database is established at each WFOA 7-day digital forecast database is established at each WFO Forecasters interactively modify the contents of the database according to the latest observations and model guidanceForecasters interactively modify the contents of the database according to the latest observations and model guidance NWS text, tabular, voice, and graphical products are generated from the databaseNWS text, tabular, voice, and graphical products are generated from the database The database itself is provided as an NWS product to customers and partnersThe database itself is provided as an NWS product to customers and partners

5. Symposium 50 th Anniversary Operational NWP Approaches to Forecaster Interaction Matrix EditingMatrix Editing –Interactive Computer Worded Forecast (USA) –SCRIBE (Canada) Grid EditingGrid Editing –Graphical Forecast Editor (USA) –RiPP (Sweden) Object EditingObject Editing –Forecast Production Assistant (Canada) Interactive Model InterpretationInteractive Model Interpretation –Slider Bars (USA) 4D Field Modification4D Field Modification –Horace (UKMET)

6. Symposium 50 th Anniversary Operational NWP

8. NDFD Definition Contains a seamless mosaic of NWS digital forecastsContains a seamless mosaic of NWS digital forecasts Is available to all users and partners – public and privateIs available to all users and partners – public and private Allows users and partners to create wide range of text, graphic, and image productsAllows users and partners to create wide range of text, graphic, and image products

9. Symposium 50 th Anniversary Operational NWP NDFD Benefits Provides weather information to “drive” custom applications developed by private sectorProvides weather information to “drive” custom applications developed by private sector - Decision support systems that fit the forecast to the problem - Weather information along a path - Text generation in more than one language - Forecasts for vehicles and hand-held devices with GPS - Controls for smart appliances (e.g., heating, cooling, irrigation) - Graphics for mass media

10. Symposium 50 th Anniversary Operational NWP Image of NDFD grid

11. Symposium 50 th Anniversary Operational NWP Image of NDFD grid

12. Symposium 50 th Anniversary Operational NWP Image of NDFD grid

13. Symposium 50 th Anniversary Operational NWP Image of NDFD grid

14. Symposium 50 th Anniversary Operational NWP Current NDFD experimental elements Daytime maximum and nighttime minimum temperatureDaytime maximum and nighttime minimum temperature Probability of Precipitation (12 hour)Probability of Precipitation (12 hour) Significant weatherSignificant weather Sky coverSky cover TemperatureTemperature Dewpoint temperatureDewpoint temperature Wind direction and speedWind direction and speed Precipitation amount (QPF)Precipitation amount (QPF) Snow amountSnow amount Wave heightWave height

15. Symposium 50 th Anniversary Operational NWP NDFD Resolution Spatial resolution:Spatial resolution: - 5 km grids for now - 2.5 km grids when AWIPS hardware allows Temporal resolution:Temporal resolution: - 3 hourly for days 1-3 - 6 hourly for days 4-7 - as available from CPC beyond day 7 Update frequency: every hourUpdate frequency: every hour

16. Symposium 50 th Anniversary Operational NWP NDFD – next steps Spatial resolution that better resolves complex terrainSpatial resolution that better resolves complex terrain Temporal resolution that resolves diurnal cycle and can support terminal forecastsTemporal resolution that resolves diurnal cycle and can support terminal forecasts More frequent than hourly updatesMore frequent than hourly updates Additional forecast elements Additional forecast elements – Derived parameters, fire weather, marine – Probabilistic – Digital forecasts from NCEP service centers – 3D grids capable of supporting aviation services

17. Symposium 50 th Anniversary Operational NWP NDFD Value added to Models Accuracy at observation points – comparable to GFS MOSAccuracy at observation points – comparable to GFS MOS Accuracy at gridpoints – need “Record of Analysis”Accuracy at gridpoints – need “Record of Analysis” Variance – hourly fields exhibit systematic diurnal biasVariance – hourly fields exhibit systematic diurnal bias Terrain detail – apparent for all 7 daysTerrain detail – apparent for all 7 days Spatial consistency – problematic across WFO borders (esp. hourly fields)Spatial consistency – problematic across WFO borders (esp. hourly fields) Timeliness and completeness – problematicTimeliness and completeness – problematic Continuity between issuances – presumably betterContinuity between issuances – presumably better

18. Symposium 50 th Anniversary Operational NWP A Good Model “First-Guess” Spatial resolution that resolves complex terrainSpatial resolution that resolves complex terrain Temporal resolution that resolves diurnal cycle and can support aviation forecastingTemporal resolution that resolves diurnal cycle and can support aviation forecasting Predictands that match operational needPredictands that match operational need Good continuity from run to runGood continuity from run to run Hourly updates based on latest observationsHourly updates based on latest observations Quantification of forecast uncertaintyQuantification of forecast uncertainty

19. Symposium 50 th Anniversary Operational NWP IFPS/NDFD in a nutshell from teletype text… …to digital data streams