1. CPC Extended Range Forecasts Ed O’Lenic NOAA-NWS-Climate Prediction Center Camp Springs, Maryland ed.olenic@noaa.gov 301-763-8000, ext 7528

2. Outline - overview Weather versus climate Current status of CPC’s forecast system Schematic of the forecast system/process Outlook schedules/formats/tools/process Verification Threats, heat wave, wind chill products Outline – over-view

3. WEATHER vs. CLIMATE Smooth curve = 30 year mean (climatology) Wildly oscillating curve = daily “weather” Subtracting the climatology and performing a 31-day running mean reveals the low-frequency signal or short-term climate variations we are trying to predict.

4. CPC Forecast system schematic

5. Forecast Process Schematic Dynamical model forecasts/multi- model ensembles Recent observations Historical observations.. Verifications/Statistical tools Downscaling, Analogs, Composites WEB PAGES/AUTOMATED DATABASES Peer-reviews of the forecast tools and of the penultimate forecast via web/telephone conference with partners and through local discussions (map discussions,sanity check, conference calls, etc…) Forecaster-created or automated products Dissemination to public

6. Z500 die off

7. Six-to-Ten Day and Week 2 Outlooks and Week 2 Outlooks

8. 6-10 DAY/WEEK 2 OUTLOOK SCHEDULE/LEADS Each day, CPC prepares and disseminates outlooks for 6-10 days (lead time of 5 days) and week 2 (days 8-14, lead time of 7 days). Each of these outlooks is accompanied by forecast maps of –1) 500 mb height and 500 mb height anomalies over the Northern Hemisphere, forecast maps of –2) surface temperature and –3) precipitation for the continental U.S. and Alaska and a single bulletin, FEUS40, giving a prognostic discussion for both forecasts and a table of state- by-state forecasts for each forecast. On Monday through Friday, including holidays, the outlooks are prepared by a forecaster who draws the maps, writes the bulletin and composes the table. On Saturday and Sunday only automated versions of the maps and the tables are disseminated.

9. 6-10 day/week 2 Outlook Categories, Probabilities 6-10 day/week 2 outlooks are prepared for 5-day/7-day average temperature and total accumulated precipitation category. Three categories are used (terciles). These are BELOW-,NEAR- and ABOVE-normal, for temperature, and BELOW-, NEAR- and ABOVE-median for precipitation. The contours on the maps depict the TOTAL probability of the occurrence of the indicated category. Contours of the climatological normals are also shown.

10. Recent Changes to Procedures From 3 times/week to daily in October 2000 Automated weekend forecasts from October 2000 Percent probability format from October 2000 Alaska and week 2 added October 2000 Automated wind-chill product introduced Nov 2001 Bias-corrected precipitation forecast tool and other improvements added in the fall of 2001

11. 6-10 day/week 2 process schematic Multi-model ensemble 9:00 AM Weighted average of model 500 hPa height Downscale: get surface weather from 500 mb height via analogs, regression, neural network. RR Forecaster formulates maps of predicted T, P, PMD bulletin Disseminate via web, AWIPS, FOS 3-4 PM R = Forecaster reconciliation of tools required

12. Forecast Maps and Bulletins Each day,between 3 and 4 PM Eastern Time, CPC issues a set of 6-10 day and week 2 outlooks. These are formulated by a forecaster (Monday through Friday) and are automated on weekends. There are two 500 mb height maps, two surface maps and a single bulletin. Sample 6-10 day outlook 500 mb height and anomaly forecast map from CPC web page.

13. Sample 6-10 day average T outlook

14. Sample 6-10 day 5-day total precipitation outlook from CPC web page. Sample 6-10 day P outlook

15. 6-10 day/week 2 Forecast Tools Examples of the variety of tools used in preparing the 6-10 Day and week 2 outlooks. These forecast tools consist of: 1.Statistical: Klein, Neural Network, analogs, teleconnections, calibrated MRF precipitation 2.Dynamical: hrMRF, MRF ensembles, ECMWF, dAVA, CDC calibrated MRF

16. 23 years of daily forecasts (1 forecast/day) out to week 2, October 1978-present (MRF T62) Operations: Run a 15-member ensemble in real-time using the same model as is used to create the archive. Ensemble mean for 8-14 days Calculate anomalies using the 23-year model climatology (bias corrected) Assume the mean week 2 spread is determined by the error variance of the 23-years of forecasts. A Simple Calibration Scheme Climatology of model: mean, standard deviation, error variance

17. Uncalibrated forecasts reliability

18. Calibrated forecasts reliability

19. ECMWF upper-air height forecasts, analog

20. MRF Ensemble upper-air- height forecasts, analog

21. Official 6-10 day 500 hPa forecast

22. Teleconnections (TC) Definition: Composite of those maps, for a calendar month, with largest + (top 10%) or – (bottom 10%) 500 hPa height at a specified space point from 1950-1999 (~150 maps). Forecasters compute TC on the major anomaly centers (base points) of 500 hPa forecast maps. If there is a strong relationship between the base point centered at the largest anomaly, and distant points, the TC map will display large correlation values at the base point and at the distant centers. If there is no strong historical relationship, only the correlations at the base point will be large. Weak TC indicate the pattern is probably transient and not as likely to be well predicted by the model as would a persistent (strong TC) pattern.

23. Teleconnection on 500 hPa weighted mean anomaly center at 140W/53N(-)

24. Composite of observed T, P anomalies associated with teleconnection on - 500 hPa anomaly at 53N 140W

25. T prediction analog maps

26. Week 2 forecast tools from CDC

27. MRF Precipitation Bias Correction: Week 2

28. Z500 d+8 skill

29. Z500 d+11 skill

30. T850 d+8 skill

31. T850 d+11 skill

32. Official 8-14 day T, P forecast The final forecasts of temperature and precipitation. The forecasters reasoning is given in the bulletin (next slide).

33. 6-10 day Monthly Average Skill Scores

34. U.S. Hazards Assessment

35. Definitions of Threats Listed at left are the nominal definitions of threats. Because prior conditions play a role in the impact of anomalies on the level of threat, the definitions listed are only guidelines, to be used along with knowledge of prior conditions, by the forecaster in assigning threats. Research is required to objectively determine thresholds for threats at a large number of locations.

36. New medium range automated products CPC and MDL have collaborated to create new MOS-based products which are produced and disseminated automatically. Heat index outlooks for 6-10 and 8-14 days Wind-chill outlooks for 6-10 days Average temperature outlooks for 6-10 days

37. Excessive Heat Outlooks

38. Excessive Heat probabilities

39. Wind-chill Outlooks

40. Average T Outlook

41. The End