1. 4-6 May 2009 Co-hosted by Naomi Surgi, Mark DeMaria, Richard Pasch, Frank Marks 4-6 May 2009 Co-hosted by Naomi Surgi, Mark DeMaria, Richard Pasch, Frank Marks OVERVIEW Hurricane Diagnostics/Verification Workshop OVERVIEW Hurricane Diagnostics/Verification Workshop

2. Purpose of Workshop: To bring together expertise in the hurricane research and operational communities to launch a concerted diagnostics activity to improve NHC’s numerical guidance Objective/Goals: to provide feedback to both operational model developers and to hurricane forecasters for near term transition into operations and to research modelers to develop useful methods for assessing forecast quality in various phases of model development. Observations from both satellite and in situ platforms…… and model verification are critical to assist this effort

3. Max Mayfield left this for me on my desk (after he worked a mid shift)………… !!! Statistical Dynamical

4. Over the past decade(s) – LOTS of model data has been generated by the various global and regional operational hurricane models, e.g. the NCEP GFS, NOGAPS, UKMO, the GFDL model and for the past two seasons the HWRF. For GFDL, HWRF….for track AND intensity Bad forecasts, good forecasts (sometimes very surprisingly so)….. But little feedback as to why….. Also, sometimes model biases are noted, e.g. GFS northward bias in central tropical ATL; NOGAPs strong westerly bias; GFDL strong intensity bias (sheared environments); …… HWRF? Are these systematic model biases? Vary w/basin? Artifact of the season? Related to initial errors; physics? Most importantly (once identified) HOW TO FIX? PERFECT !

5. Some examples

6. HWRF GFDL HURRICANE FAY

7. H. GUSTAV HWRF Several models had skillful 5 day forecasts when Gustav was still east of Jamaica targeting the central LA coast Most model forecasts did not target Galveston for IKE landfall until ~ 36 hrs. before landfall H. IKE

8. HWRF GFDL HURRICANE BERTHA

9. GLOBAL vs. Regional NORBERT

10. HWRF Track Hurricane Flossie Fcst 081200 Fcst 081212 FLIP FLOP

11. TS BARBARA GFDL, AVNO, UKM, NGPS, HWRF None of the models could get a grip on this forecast!

12. Hurricane Henriette GFDL Nearly a perfect forecast…..

13. HWRF 126H FORECAST OF HURRICANE DEAN CAT5 CAT2 HWRF forecast both landfall intensities Can you trust this forecast?

14. We’re making progress…but many difficult problems ahead Felix - Vmax (kts) Humberto 2007 9/09-9/12 Franklin - Vmax (kts)

15. Dennis Wilma Track impacts intensity

16. Interesting way research models show forecasts Need to be very careful……

17. Research model forecasts of storm intensity for Hurricane Katrina showing benefit of high (1.6 km) resolution High-res models (1.6km) NHC Forecast Obs Katrina Landfall GFDL model Global models

18. High-res models (1.6km) NHC Forecast Obs Katrina Landfall GFDL model Global models Research model forecasts of storm intensity for Hurricane Katrina showing benefit of high (1.6km) resolution Intensity Forecast of HurricaneKatrina 0000 UTC 27 August 2005 HWRF model HWRF

19. IN FACT: From 114 hrs to 60 hrs before landfall, seven HWRF forecasts predicted rapid intensification of Hurricane Katrina, predicting Category 5 Hurricane Three HWRF forecasts predicted Category 3 landfall for Hurricane Katrina Three HWRF forecasts of max. intensity coincided with observed maximum intensity

20. Operational models are becoming very complex…. Coupled to ocean, waves, land surface model Same issues….. We must begin to identify systematic biases What observations do we have? Are still needed? Workshop objective: When we leave here…… What are the activities? WHO is going to do what?

21. Housekeeping HousekeepingAgenda Enough time for discussion THANK YOU HFIP for support