1. Developments in Seasonal Atlantic Basin Tropical Cyclone Prediction Phil Klotzbach Department of Atmospheric Science Colorado State University Ph. D. Defense July 9, 2007

2. Acknowledgments Mentor – Dr. Gray Ph. D. Advisor – Dr. Schubert Ph. D. Committee Members – Drs. Mielke and Pielke CSU Student Colleagues – Eric Blake, Matt Eastin, Brian McNoldy, Stacey Seseske, Wes Terwey, Jonathan Vigh Friends and Family – Especially my parents for providing me with an outstanding home education National Science Foundation and Lexington Insurance Company

3. Outline Introduction Data Atlantic Basin Multi-Decadal Variability Seasonal Forecast Developments 2007 Hurricane Forecast United States Landfalling Hurricane Probability Webpage Hurricanes and Global Warming

4. Introduction The globe’s atmosphere and oceans function as one unit. Current circulation features have considerable precursor information regarding the coming month’s or coming season’s amount of hurricane activity.

6. OUTGOING LONGWAVE RADIATION ABSORBED SOLAR RADIATION LATENT HEAT FLUX NET ENERGY BALANCE TEMPERATURE OCEAN HEAT FLUX SUBSURFACE HEAT STORAGE SENSIBLE HEAT AND POTENTIAL ENERGY FLUX THERMAL INERTIA Flow diagram for climate modeling, showing feedback loops. From Robock (1985).

7. Arago’s Admonition: “Never, no matter what may be the progress of science, will honest scientific men who have regard for their reputations venture to predict the weather.”

8. So easy a caveman could do it.

9. Data NCEP/NCAR Reanalysis – globally gridded (2.5° x 2.5°) dataset for many surface and upper-level features from 1948-present National Hurricane Center “best track” dataset – best estimates of six-hourly location and intensity of tropical cyclones

14. 12 3 H H Courtesy of John Marshall (MIT)

15. 1860 1900 1940 1980 2020 THC - Strong (Goldenberg et al. 2001)

16. Top 20 AMO Years – Bottom 20 AMO Years (1878-2006) - SLP

17. AMO Index 1.2 2.6 1.5 3.9 Major Hurricanes per Year

18. STRONG THCWEAK THC gyre -gyre + + + + – – – SLPA –SLPA +

21. Date 8 Dec. 3 Apr. 31 May 3 Aug. 4 Sep. 2 Oct. Seasonal Forecast XXXX Monthly Forecast XXX

22. New Forecast Development Methodology Use predictors using surface data from the two months prior to the forecast issue date Hindcast Net Tropical Cyclone activity metric only Develop forecast on data from 1950-1989 Test forecast on “independent” data from 1990-2004 New forecast schemes must show comparable skill in both time periods

23. EQ. Oct-Nov SLP 3`3` 2 1 New December Forecast Predictors Oct-Nov SST Oct-Nov SLP

24. Developmental

25. Applied

26. EQ. Feb-Mar SST 3`3` 2 1 New April Forecast Predictors Feb-Mar SLP Feb-Mar SST

27. Developmental

28. Applied

29. EQ. Predicted July-Nov AMM Index 2 1 New June Forecast Predictors April-May SST 3`3`

30. Developmental

31. Applied

32. EQ. 1 2 New August Seasonal Forecast Predictors June – July SST 3 June – July SLP Pre 1-August NSD S of 23.5°N, E of 75°W 4

33. August Statistical Scheme – Hindcast Skill for NTC (1900-1948) Observations Hindcasts

34. Observations Hindcasts August Statistical Scheme – Hindcast Skill for NTC (1949-2005)

35. NSNSDHHDMHMHDNTC Top 109.257.95.226.52.77.5113.0 Bottom 104.324.52.48.20.71.839.2 Ratio (1900-1948) Ratio (1949-2005) 2.1 2.4 2.6 2.2 2.5 3.2 3.7 3.9 4.9 4.2 7.3 2.9 3.4 Top 10 – Bottom 10 Atlantic Basin TC Ratios for 1900-1948 Period Using Forecast Equations Developed on 1949-1989

36. 16 Landfalls 3 Landfalls

37. DecemberAprilJuneAugust Top 107676 Bottom 102222 Ratio3.503.003.503.00 Top 10 versus Bottom 10 Florida Peninsula and East Coast Major Hurricane Landfalls based on NTC Hindcasts (1949-2005)

38. Skill of Seasonal Forecasts

39. Correlation of CSU Forecasts of NTC with Observations

40. Skill of Cane and Zebiak Forecast Model for Nino 3 SST

42. 2007 Hurricane Predictions

43. Forecast Parameter Statistical Forecast Analog Forecast 31 May 2007 Forecast 1950-2000 Climatology Named Storms (NS)15.712.7179.6 Named Storm Days (NSD)80.571.28549.1 Hurricanes (H)9.77.595.9 Hurricane Days (HD)40.238.94024.5 Major Hurricanes (MH)3.7 52.3 Major Hurricane Days (MHD)8.211.4115.0 Accumulated Cyclone Energy (ACE) 15815017096 Net Tropical Cyclone Activity (NTC) 164158185100 2007 FORECAST AS OF 31 MAY 2007

45. PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS FOR 2007 1)Entire U.S. coastline – 74% (average for last century is 52%) 2) U.S. East Coast including Peninsula Florida - 50% (average for last century is 31%) 3) Gulf Coast from the Florida Panhandle westward to Brownsville - 49% (average for last century is 30%) 4) Expected above-average major hurricane landfall risk in the Caribbean

47. New Landfalling Hurricane Web Application Currently Available at the following URL: In partnership with the GeoGraphics Laboratory – Bridgewater State College, Bridgewater MA http://www.e-transit.org/hurricane

48. Areas for which Landfall Probabilities are Issued U.S.1 Sub – U.S.2 Regions11 Sub – Regions55 Counties205

49. REGION 2 - TEXAS & LOUISIANA V A J C C C L H J O (a) (c)(b)

52. Future Work Monthly Probabilities User-Selected Probabilities (Daily, Weekly Periods) Potential Damage

54. Open Atlantic Ocean Differences 1933 Hurricane Season 2005 Hurricane Season Courtesy of Chris Landsea (2006)

55. Figure 4 – From Webster et al. (2005)

56. Basin1986-19951996-2005Ratio (1996-2005 / 1986-1995) North Atlantic1025250% Northeast Pacific372362% N. Atl. + NE Pac.4748102% Northwest Pacific7576101% North Indian34133% South Indian2636138% South Pacific1316123% Northern Hemisphere125128102% Southern Hemisphere3952133% Global164180110% Category 4-5 Hurricanes by Ten-Year Periods

57. BasinCorrelation with ACECorrelation with Cat. 4-5 Hurricanes North Atlantic0.570.39 Northeast Pacific0.580.59 Northwest Pacific-0.28-0.11 North Indian-0.07-0.29 South Indian-0.32-0.18 South Pacific-0.38-0.20 Correlation between Boreal Summer Basin-wide Sea Surface Temperatures and Tropical Cyclone Activity (1986-2005)

58. Klotzbach (2006)

59. Kossin et al. (2007)

60. ATLANTIC THC STRONG ATLANTIC THC WEAK GLOBE COOLING GLOBE WARMING CAT 3-4-5 TRACKS

61. PENINSULA FLORIDA LANDFALLING MAJOR HURRICANES

62. 1925-1965 41 Years 1966-2006 41 Years 2050 Background 280 ppm 310 ppm 365 ppm 39 Landfalls 22 Landfalls 0.95 year 0.54 year CO 2 zero

63. Conclusions An active hurricane season is predicted in 2007 The recent increase in Atlantic basin hurricane activity is largely driven by natural multi-decadal variability

64. Questions???