The National Hurricane Center

Transcription

1 The National Hurricane Center Where we are and where we hope to go Bill Read, Director National Hurricane Center

2 U.S. HURRICANE FORECAST SERVICE HISTORY MODERN ERA HIGHLIGHTS 1935: Began 24 hour forecast and 6 hour cycle 1961: Hurricane Carla - 2-day forecasts introduced. 1964: 3-day forecasts begin. 1988: NHC assumes responsibility for E. Pacific. 2003: 4-day and 5-day forecasts begin.

3 2008 Hurricane Ike 1900 Galveston Storm

4 THE U. S. HURRICANE WARNING PROGRAM THEN AND NOW 1900 GALVESTON HURRICANE 2008 IKE ~ 8000 COASTAL DEATHS ~ 20 COASTAL DEATHS (as of 10/28/08) David J. J. Phillip-Pool/Getty Images

5 Six hour Forecast Cycle Continuous data ingest Diagnosis by Specialist Run models Prepare products Coordinate internally and externally Communicate

6 Forecast parameters Track - direction and speed Intensity maximum wind and radii Storm surge Rainfall Probabilitistic

7 A Few of the Wind Issues 1 minute average wind basis for intensity forecast not measured often Abrupt change in friction at land fall changes wind characteristics Sensor/power failure land observation systems Building codes based on 3 sec gusts (also not measured often)

8 Grand Turk, Ike

9 A Weakening Hurricane It loses its energy source of warm water. It encounters increased surface friction over land. Major hurricane will lose ½ wind speed in 12 hours

10 Storm Tide Facts Close to 8000 died in the Galveston Hurricane of 1900, most by storm surge. Hurricane Carla in 1961 generated a 22 foot storm tide in Matagorda Bay. Hurricane Katrina in 2005 generated a foot storm tide on the Mississippee coast. Tropical Storm Frances generated a foot storm tide

11 Cuba, 135 mph

12 Bolivar, Friday September 12

13 Bolivar peninsula 9/15/08

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15 Storm Surge Challenges Develop more effective warning system Improved real time forecasting of surge Wave forecasts Expand use of storm surge probability forecasts Modernize tool kit for decision makers and public Educate educate educate

16 What Do We Mean by Forecast Uncertainties? Average NHC Track Errors (Atlantic Basin) Track errors have been cut in half since 1990

17

18 120 Hour Decision point * Ike at 2pm

19 96 hour decision point * Ike 2 AM Sat

20 72 hour decision point * Ike 2 am Sat

21 Category 3 MEOW

22 Only a Category 2?

23 Note the category 2 zone

24 Hurricane Ike Track models

25 Track Forecast Challenges Goal: reduce error by 50% in 10 years Last 20 years of improvement closely tied to improved computing capability and resultant higher resolution/more complex models Assess predictability What model improvements needed to reduce uncertainty by 50% Explore extending forecast to 7 days

26 Hurricane Watch Issued 48 h decision point

27 Hurricane Watch >10% prob

28 Prob >5 feet when Watch issued

29 Prob>10 feet

30 Extratropical Storm Surge estimate

31 Hurricane Warning Issued 24 hour decision point for highest risk

32 Chance >5 Feet Warning issued

33 Warning issued, prob >10 feet

34 Current graphic

35 Addition of inland hurricane warning (Inland) Hurricane Warning

36 Proposed Hurricane warning (wind) and storm surge warning graphic Storm Surge Warning

37 (Inland) Hurricane Warning H H Storm Surge Warning

38 Intensity Forecast Goal: forecast rapid intensification out 24 hours Better define processes behind rapid change in intensity Developing models that capture intensity change processes Observing system to initialize models Computing capacity to run models Define processes that result in changes to size and shape of wind field

39 No Progress With Intensity

40 DEAN FELIX HUMBERTO

41 Tropical Cyclogenesis Goal:forecast formation 24h in advance Graphical Tropical Weather Outlook with 3-tier probability of formation Internal experiment with probability for rapid intensification Genesis in the Gulf with rapid intensification a big challenge due to loss of lead time (Audrey, Alicia, Humberto)

42 First year of Genesis forecasting Graphical Tropical Weather Outlook

43 Hurricane Size

44 Remote Sensing Challenges Satellites Polar and Geostationary More complex sensor technology (higher resolution, new NEXRAD in space, eg) Traditional Aircraft Reconnaissance oceanographic sensors Unmanned aircraft (Aerosonde, WISDOM) Big $$$

45 Rainfall Issues The speed of movement is primary influence on amount of rain. Rule of thumb...speed of the storm divided into 100 = maximum rainfall hard to beat Mesoscale-storm storm features determine distribution of excessive rain forecast improvements driven by mesoscale model advancements TC excessive rain events usually well above 100 year event

46 As to the people problem with Hurricanes I m out of time

47 Be Prepared!