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Products and Forecasts - Examples and experiences

This presentation highlights various examples and experiences with products and forecasts, including the National Digit Guidance Database (NDGD) and the National Digit Forecast Database (NDFD). It also discusses the impact of resolution on forecast accuracy and showcases case studies on hurricanes, typhoons, derecho, and storms like Hurricane Sandy and the 2015 NE Blizzard. Additionally, it highlights the importance of ensemb ling and probabilistic forecasting.

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Products and Forecasts - Examples and experiences

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  1. Products and Forecasts- Examples and experiences Yuejian Zhu and Hong Guan Ensemble Team EMC/NCEP/NWS/NOAA Presents for NWP Forecast Training Class March 31, 2015, Fuzhou, Fujian, China

  2. Background • NDGD • National Digit Guidance Database • Guidance's are produced from NWP output, post process and et al. • NDFD • National Digit Forecast Database • Forecasts are issued from WFO forecasters based on all different guidance • Coverage and resolution • CONUS – 2.5km • Alaska – 3km • Hawaii – 2.5km • Puerto Rico – 2.5km • Guam – 2.5km

  3. US NWS NDFD forecast elements and projections (2014)

  4. High Impact Weather and Extreme Forecast

  5. Hurricane Katrina (2005)

  6. Hurricane Katrina (2005) 0-120 hours 120km radius Early prediction: Friday – August 26 NHC’s prediction ECMWF ensemble forecast: Strike probability from Friday – August 26

  7. Typhoon Morakot (2009)

  8. Courtesy of Bill Kuo

  9. Courtesy of Bill Kuo

  10. Resolution makes difference for Typhoon Morakot Ini: 2009080600 T126 ensemble T190 ensemble Most models do not make right forecasts Ini: 2009080700 T126 ensemble T190 ensemble 10

  11. Typhoon Megi (2010) 2010101512 2010101612 NCEP CMC ECMWF 3-ENS 2010101712 2010101812

  12. Derecho (2012)

  13. A moderate risk area was issued by the SPC for the areas downstream of the derecho. It was later expanded eastward. Derecho (2012) Date(s) June 29–30, 2012 Duration ~18 hours (10:00 AM-4:00 AM) Track length ~800 Miles Peak wind gust 91 mph (Fort Wayne, Indiana) Largest hail 2.75 Inches (Bismarck, Illinois) Fatalities 28 fatalities Damage $2.9 billion[1] Areas affected United States Midwest, United States Mid- Atlantic

  14. Sandy Case Study for NEXT GEFSPeriod: 10/22 – 10/28/2012Named: 10/23/2012 Yuejian Zhu EMC/NCEP September 15 2014 Acknolegements: DingchenHou, Xiaqiong Zhou and Jiayi Peng

  15. 00UTC Bimodality? Thick blue: ensemble mean Para: T574L64 (33km) Opr: T254L42 (55km) 20121022 (8 days) Red arrow means good forecast 06UTC

  16. 12UTC Bimodality? Thick blue: ensemble mean Para: T574L64 (33km) Opr: T254L42 (55km) 20121022 (7.5 days) 18UTC

  17. 00UTC Para: T574L64 (33km) Opr: T254L42 (55km) 20121026 (4 days) 06UTC

  18. 00UTC Para: T574L64 (33km) Opr: T254L42 (55km) 20121028 (2 days) 06UTC

  19. Short Summary for Sandy case • Higher resolution and new model improve the forecast skill for most lead-time, especially for longer lead-time (day 7-8). • Higher resolution and new model have excellent predictability around 8-days • Bimodality of forecast tracks is clearly for early lead-time – around 30-32N • Very good forecasts for short lead-time (less than 4-5 days) of both production and parallel • Problem/concern: • Forecast inconsistency from cycle to cycle since initial condition changes, especially for Oct. 23 - 24

  20. March 6 2013 – winter storm “Saturn” Heavy, wet late season snowstorm likely to paste D.C., Mid-Atlantic Wednesday Tuesday night to Wednesday night for potential of at least 5 inches of snow for entire region* From 11:47 AM Update: 1:55PM

  21. FEDERAL OFFICES in the Washington, DC, area are CLOSED. Emergency and telework-ready employees (employees with approved individual telework agreements) required to work must follow their agency’s policies, including their approved individual telework agreement All Howard County public schools and offices are closed today, Wednesday, March 6, 2013. All evening activities in schools, both school-sponsored and community-sponsored, are canceled. This includes high school athletic practices and games.

  22. Review of 2015 NE Blizzard01/26 12UTC – 01/27 12UTC 2015 Yuejian Zhu EMC/NCEP/NWS Jan. 27 2015 Acknowledgements: Hong Guan, Yan Luoand Xiaxiong Zhou ESRL’s EFI maps

  23. WFO forecast (48 hours accumulation)

  24. CCPA 24 hours accumulation (mm) ENDING 12 UTC 20150128 ENDING 12 UTC 20150127

  25. Small and large uncertainty. 1 day (large uncertainty) = 4 days (control) = 10-13 days (small uncertainty) Ensemble Forecast - Uncertainty Toth and Zhu (2001)

  26. Ensemble Based Probabilistic Quantitative Precipitation Forecast (PQPF) Valid: 2015012612 – 2015012712 Amount 24hr >25.4mm (1 inch) Initial Time 2015012400 2015012500 NCEP GEFS PROD/PARA Forecast difference 2015012600 PROD PARA

  27. Ensemble Based Probabilistic Quantitative Precipitation Forecast (PQPF) Valid: 2015012612 – 2015012712 Amount 24hr >25.4mm (1 inch) Initial Time 2015012100 2015012200 2015012300 ECMWF PARA PROD

  28. Ensemble Based Probabilistic Quantitative Precipitation Forecast (PQPF) Valid: 2015012612 – 2015012712 Amount 24hr >25.4mm (1 inch) Initial Time 2015012400 2015012500 Here is the difference EC’s ensemble predicted 50%+ chance for 1 inch prcip over NY city 2015012600 PROD PARA ECMWF

  29. NCEP GEFS failed on Oct. 3-4 2014 • First fail – 18UTC Oct. 3rd 2014 – Friday • No product for GEFS, SREF, Wave and NAEFS • Second fail – 12UTC Oct. 4th 2014 – Saturday • Delayed 3hrs for all products and downstream • Where is the problem? • Failed on first integration time step • Point to short wave radiation • In fact, the problem is longwave radiation code • secdiff(j) = a0(j) + a1(j) * exp( a2(j)*pwvcm) < 0.0 • It was never happened before • Protect – cost? • Morning of Oct. 10th 2014 – Friday • Announced we found a problem

  30. The art of good forecasting A2 持续性预报 Persistence 最好的数值预报 World Best NWP 经验预报 Meteorologist A 最好的预报 Modified NWP forecast

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