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The model upgrade – from the forecasters point of view

The model upgrade – from the forecasters point of view. Thomas Schumann, Deutscher Wetterdienst, Zentrale Vorhersage D-63067 Offenbach, Germany E-Mail: Thomas.Schumann@dwd.de. Outline 1. Introduction - current situation 2. How to get more benefit from hi-res modelling

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The model upgrade – from the forecasters point of view

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  1. The model upgrade – from the forecasters point of view Thomas Schumann, Deutscher Wetterdienst, Zentrale Vorhersage D-63067 Offenbach, Germany E-Mail: Thomas.Schumann@dwd.de ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  2. Outline • 1. Introduction - current situation • 2. How to get more benefit from hi-res modelling • 3. Case studies • Conclusions ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  3. 1. Introduction - current situation Since Nov 2005: Model upgrade . Before current Determin fc T511 L60 T799 L92 EPST256 L40 T399 L62 Data archived in grid Determin fc0,5 x 0,5 0,25 x 0,25 EPS1,0 x 1,0 0,5 x 0,5 Objective of the upgrade: Improvement of the Prediction of severe weather events in the early medium range Problem: Using full resolution field size increased by 4 times ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  4. Advantages of the upgrade: • Better representation of the orography („smaller“ items of • German orography like Harz highlands and Upper Rhine valley) • on weather phenomena detected – luv and lee effects • Severe weather related pattern on a smaller scale (sub-synoptic) • detectable (precipitation forecasts) – looks like more realistic • EPS: seems to be more sensitive for severe weather related • signals (EFI, probabilities if full resolution will be used) • EPS products more accepted by the forecasters • graphics from the member state web page included in warning • activity reports of the DWD ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  5. Disadvantages: . Model run Before after the upgrade Available at 00 UTC 06:00 /07:45 / (UTC)- approx 12 UTC 18:00 19:45 An earlier dissemiation time would be highly appreciated because the main decisions has to be made earlier ! • Coordination of the forecast and warning activity between • Central forecasting and the regional weather centers • Most important Medium-range products: issued before 07:00 UTC • Synoptic Guidance products in the evening: in preparation • between 17 and 18:30 UTC – issued not later than 19:00 UTC Way out:Using the previous model run (forecasters used to do so before the introduction of the earlier dissemination time) ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  6. 2. How to get more benefit from hi-res modelling Range of well-tried medium-range forecast products offered in the web - unchanged for at least 4 years ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  7. User should be able to define his area of interest to zoom in What could be done better? How the hi-res model could be better presented in the web / used? ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  8. Integration of the GRIB files into NinJo – Allocation of patterns, boundaries, … solved Resolution of GRIB´s parameter-dependent • better allocation of synoptic relevant patterns • legend, colour code of the plot etc should be kept Introduction of boundaries ? ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  9. Suggestion 1: Earlier truncation - cost – benefit ratio R. Buizza, 2003 Back to an earlier dissemination of most important forecast products ? • det model: HiRes (T799) up to H+180 • only, beyond H+180: T511 • > H+240: T399 ? • EPS: Full res (T399) up to H+180 • beyond H+180: T255 • > H+240: T159 ? From a forecasters point of view: What is the scientific value of a d+10 (or longer) T799 forecast? How much cpu time the truncation would help to save ? Suggestion 2: Starting a shorter pre-run of the det model (up to H+84) ? ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  10. User-choosen EPSgram Short-range EPSgram User has to select Default EPSgram (as usual) „Full-range“ EPSgram How the hi-res EPS could be better presented / used? - Relaunch of the EPSgrams • additionally Introduction of a short-range EPSgram (up to H + 84 by 3 h-steps – if possible) • Introduction of additional weather parameters (database perturbed forecasts in MARS – see next slide) ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  11. User-choosen EPSgram Available as short-range and full-range EPSgram ! Default EPSgram (as usual) 850 hPa (or 500 hPa) temperature Z 500 hPa 2 m dewpoint temperature Msl pressure Precip (as in the standard EPSgram) 10 m wind gust or 850 hPa wind speed instead 10m wind speed TMax, TMin instead of T ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  12. Short-range EPSgram • Time steps / preprocessing time • every 3 hours (excerpt fx and TMax / TMin – here every 6 hours) • Maximum lead time 84 hours Default and user-choosen EPSgram ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  13. Way out: Ask EFI ! Current EPSgram column Overshooting of the blue boxes: caused by one or by 12 members ? Is this a early warning signal for a severe precip event ? Precip signal up to 0.6 ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  14. Current EPSgram column upper extreme 5 % Upper 25 % Next 10 % Next 10 % 50 % lower 25 % lower extreme 5 % Suggestion: Including more information into a column Revised EPSgram column „needle“ of the distribution: caused by 2 EPS Runs only Value of a share in € Advantage: Outliers will be clearly diagostized and distigueshed in relation to the distribution function of the event ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  15. 3. Case studies • Squall line • 20 May, 2006 ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  16. Analysis, Z500 / T850 hPa, 20 May 06, 18 UTC MSLP Analysis, 20 May 06, 18 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  17. 10m wind gusts (kmph) and Strokes, 20 May, 15 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  18. 10m wind gusts (kmph) and Strokes, 20 May, 18 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  19. 10m wind gusts (kmph) and Strokes, 20 May, 21 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  20. 10m wind gusts (kmph), 20 May, 12 … 18 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  21. 10m wind gusts (kmph), 20 May, 18 … 24 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  22. 10m wind gust, det model, 20 May 06, 00 UTC 09 – 12 UTC 12 – 15 UTC 15 – 18 UTC 18 – 21 UTC ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  23. 15 – 18 18 – 21 UTC fx > 25 mps 12 – 15 fx > 20 mps 15 – 18 18 – 21 UTC 12 – 15 ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  24. COSMO-LEPS: 10m wind gusts in excess of 25 m/s 19 May, 12 + 24 … 48 h COSMO-LEPS: 10m wind gusts in excess of 25 m/s 18 May, 12 + 48 … 72 h ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  25. SRNWP PEPS: 10m wind gusts in excess of 25 m/s 19 May, 12 + 18 … 30 h ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  26. SRNWP PEPS: 10m wind gusts in excess of 25 m/s 20 May, 00 + 06 … 18 h ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  27. Observed values (6-hrly) EPSgram, 02 June 2006, 00 UTC …back to a couple of slides ago… (2nd case study) Is this a early warning signal for a severe precip event ? Candlewicks containing valuable information ! Precip signal up to 0.6 ! Event better predicted in the medium range than In the short-range ! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  28. Improvement of the prediction of sev weather events already during the early medium range 4. Conclusions • Model upgrade to T799: resolution closer to regional models • Better representation of the orography, sev weather related • pattern more realistic, … EPS products more sensitive… • Problem: Products later available (after „prime time“, field size) • Value of a 10d hires fc – Truncation – back to earlier dissemination ? • Considering ways getting more information from hires model fc´s • for web-based products (det model – zooming function) • DWD: Integration of hi-res GRIB fields into NinJo • EPS: Interaction on EPSgrams by the user • - more information into a EPSgram column (outliers) Translate EPS forecast into customer-friendly products not solved ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  29. Central Forecasting Headquarter of the DWD in Offenbach ECMWF Forecast Product Users Meeting 14 - 16 June 2006

  30. Central Forecasting In a couple of years … hopefully That´s it ! Thank you for your attention! ECMWF Forecast Product Users Meeting 14 - 16 June 2006

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