1. 1 Examples: Predicting the Extreme Events

2. 2 Recent Forecast Examples: Extreme Events West Coast – 13-14 November 1981  3-5 January 2008 Central U.S. – 3-4 April 1974  5-6 February 2008 East Coast – 18-19 February 1979  15-16 April 2007

3. 3 Rapidly Developing Pacific Storm: Not Predicted Reed and Albright, MWR, 1986

4. 4 January 3-5, 2008 West Coast Rain/Snow Event 00Z 5 January, 2008

5. 5 Madden-Julian Oscillation (MJO) Update Issued each Monday by Climate Prediction Center –http://www.cpc.ncep.noaa.gov/products/precip/ CWlink/MJO/mjoupdate.pdfhttp://www.cpc.ncep.noaa.gov/products/precip/ CWlink/MJO/mjoupdate.pdf MJO Update issued December 24, 2007: “Moderate MJO activity continues. After a short break, eastward propagation has resumed during the past week and the enhanced phase is currently centered in the western Maritime continent region… Some potential exists for a heavy precipitation event tied to tropical convection by week 3. Currently, however, details of this potential event are unclear but interests along the west coast of the US should monitor the status of the MJO during the next 1-2 weeks.”

6. 6 8-14 Day Outlook

7. Hazards Assessment

8. 8 6-10 Day Outlook

9. 9 HPC 48-h QPF ending 00Z 6 Jan Issued 00Z 1 Jan Day 4-5 Forecast 8.78 x 4-5 Day Forecast Verifying Analysis 48-h QPE ending 00Z 6 Jan

10. 10 HPC 72-h QPF ending 00Z 7 Jan Issued 00Z 4 Jan Day 1-3 forecast 10.24 x 72-h QPE ending 00Z 7 Jan Verifying Analysis 1-3 Day Forecast

11. 11 HPC 72-h PRISM adjusted snow accumulation forecast ending 00Z 7 Jan Issued 00Z 4 Jan HPC analysis of storm-total snowfall (in.) 3–7 Jan 3 Day Total Snowfall Forecast 00Z Jan 4 – 00Z Jan 7 Verifying Analysis

12. 12 April 3-4, 1974 Super Outbreak Tornado Tracks 12Z April 3 – 12Z April 4, 1974 One of the deadliest tornado outbreaks in the 20 th Century (330 fatalities) Involved over one-quarter of the country 148 tornadoes in 13 states Magnitude of event not realized until evening news – April 3

13. 13 Super Tuesday Tornado Outbreak February 5-6, 2008 –63 tornadoes, 57 fatalities –Deadliest event since ’85 –Outlook issued 6 days prior –POD 100% for tornadoes occurring in SPC watches –Average warning lead time 17 min

14. 14 Hazards Assessment February 5-6, 2008 Tornado Outbreak

15. 15 February 5-6, 2008 Tornado Outbreak Day 4-8

16. 16 February 5-6, 2008 Tornado Outbreak Day 3 Day 2 CategoricalProbabilistic CategoricalProbabilistic

17. 17 February 5-6, 2008 Tornado Outbreak Day 1 Convective High Winds HailTornado

18. 18

19. 19 East Coast Storms 22 inches of snow buries Washington D.C. area Rapid cyclogenesis off the coast Not predicted even hours in advance Presidents’ Day Storm 18-20 February, 1979 1830Z 19 Feb 1979

20. 20 1970s: The Advance from Subjective to Model-Based Forecasts 1970s Limits of Predictability Cressman, 1970 The transition to model-based forecast was caught up in the inability to predict rapid cyclogenesis like the President’s Day 1979 storm

21. 21 Predicting the April 16, 2007 Nor’easter

22. 22 Surface Analysis 48 hour precipitation Valid 12Z April 16, 2007

23. 23 Surface Analysis Valid 12Z April 16, 2007 Seven day forecast

24. 24 Surface Analysis Valid 12Z April 16, 2007 Six day forecast

25. 25 Surface Analysis Valid 12Z April 16, 2007 Five day forecast

26. 26 Surface Analysis Valid 12Z April 16, 2007 Four day forecast

27. 27 Surface Analysis Valid 12Z April 16, 2007 Three day forecast

28. 28 Surface Analysis Valid 12Z April 16, 2007 Two day forecast

29. 29 Surface Analysis Valid 12Z April 16, 2007 One day forecast

30. 30 Day 4-5 48 hr Quantitative Precipitation Forecast 48 hour observed precipitation Valid 12Z April 16, 2007