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Beyond the Category

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Beyond the Category

  1. 1. Jason Runyen Senior Forecaster NWS Corpus Christi Looking Beyond the Category
  2. 2. Tropical Cyclone Hazards Hazards Differ from Storm to Storm Storm Surge Flooding Tornadoes Flooding RainsDamaging Winds
  3. 3. Category 1-min. Sustained Winds (mph) Storm Examples Wind Impacts Tropical Depression Less than 39 mph Relatively minor Tropical Storm Between 39 and 73 Allison Can be significant 1 74 - 95 Jerry 1989 Very dangerous; will produce Claudette 2003 some damage Humberto 2007 2 96 - 110 Georges 1998 Ike 2008 Extremely dangerous; will produce extensive damage 3 111 - 130 Alicia 1983 Devastating damage Katrina 2005 Rita 2005 4 131 - 155 1900 - Galveston Catastrophic damage Carla 1961 5 > 156 Andrew 1992 Catastrophic damage Camille 1969 Saffir-Simpson Hurricane Wind Scale
  4. 4. • The maximum sustained wind in the storm • A measure of the degree of damage possible in areas that experience the maximum wind (typically the eyewall) • Link with outline of wind impacts expected with each rating: http://www.nhc.noaa.gov/aboutsshws.php What the SSHWS Indicates
  5. 5. What the SSHWS Does Not Indicate • The size of the wind field/the area impacted • The magnitude of the storm surge; scale is related but other factors are important • The amount of rain that will fall and the associated flood threat • Whether the storm will be big tornado producer NOT an overall indicator of the severity of the storm (although often interpreted that way) What the SSHWS Does NOT Indicates
  6. 6. Storm Surge Damaging Winds Tornadoes Inland Flooding
  7. 7. Hurricane Categories Saffir-Simpson Hurricane Wind Scale
  8. 8. Rapid Intensification before landfall – Winds 125 with gusts to 175 at landfall Hurricane Celia – Category 3
  9. 9. Celia Wind Impacts
  10. 10. Celia Wind Impacts
  11. 11. LARGE - FLOYD, 1999 SMALL - ANDREW, 1992 ...but both were at the same intensity of 140 kt! Variability in Hurricane Size
  12. 12. Sustained winds of 160 mph at landfall – with gusts to 200 mph Hurricane Andrew – Category 5
  13. 13. Andrew Wind Impacts
  14. 14. Cat 5 SmallCat 2 Large Moderate Damage and Power Loss over a Large Area Catastrophic Damage over a Small Area
  15. 15. Hurricane Carla - 1961
  16. 16. Tropical Storm Force Winds Hurr Force Winds
  17. 17. Tropical Storm Hermine
  18. 18. Robstown
  19. 19. Bishop
  20. 20. Bishop
  21. 21. Storm Surge Damaging Winds Tornadoes Inland Flooding
  22. 22. Historically the most deadly hazard associated with hurricanes Storm Surge
  23. 23. Bringing it all Together – Total Water
  24. 24. Surge Dependence on Size: All runs simulate a cat 4 but with different size
  25. 25. Debunking the Category Myth Cat . 4 Charley: 7 ft Cat . 3 Katrina: 27 ft Cat . 2 Ike:14 to 18 ft Cat . 1 Sandy: 13 ft
  26. 26. Sandy Katrina 940 miles 415 miles Size Comparison
  27. 27. Ike (2008) / Humberto (2007) Comparison An Extreme Size Difference
  28. 28. Historical Storm Surge Events for Texas Carla - 1961 Texas Record 22.8 Feet
  29. 29. Historical Storm Surge Events for Texas Hurricane Ike - 2008 15-20 Feet
  30. 30. Historical Storm Surge Events for Texas Galveston - 1900 15 Feet
  31. 31. Historical Storm Surge Events for Texas Corpus Christi - 1919 16 Feet
  32. 32. Storm Surge Damaging Winds Tornadoes Inland Flooding
  33. 33. 34 1921 Hurricane 36” Hurricane Alice 1954 35” Hurricane Beulah 1967 30” T.S. Amelia 1978 48” Flood 1998 30” T.S. Claudette 1979 43” T.S. Allison 2001 40” T.S. Charlie 1998 18” Hurricane Alex 2010 20+” Flood 2002 30” Historical Texas Floods from Tropical Systems
  34. 34. • 25-30” Rainfall • Record Flooding in Live Oak County • Nueces River Crested Three Rivers 49.21 ft Calallen 16 ft. • Cat 4 at landfall • $200 Million Damage • 10 Killed Hurricane Beulah - 1967
  35. 35. Tropical Storm Allison Path in Texas
  36. 36. 38 Houston, TX T.S. Allison 2001 $5.5 Billion, 41 Fatalities Tropical Storm Allison - 2001
  37. 37. Tropical Storm Allison June 2001
  38. 38. Hurricane Alex - 2010
  39. 39. Storm Surge Damaging Winds Tornadoes Inland Flooding
  40. 40. • North and Northeast moving hurricanes produce most tornadoes. • Nearly 30% develop before the tropical cyclone center reaches the coastline • 70% occur over land. • More than 90% of tornadoes occur in the right front quadrant (relative to the storm motion) of a tropical cyclone • Small and low-topped • Usually during the daytime Tornado Characteristics in Tropical Cyclones
  41. 41. Rank Name Year Tornadoes Waterspouts 1 Hurricane Ivan 2004 127 4 2 Hurricane Beulah 1967 115 3 Hurricane Frances 2004 106 4 Hurricane Rita 2005 92 5 Hurricane Andrew 1992 61 2 6 Hurricane Katrina 2005 58 3 7 Tropical Storm Fay 2008 49 8 Hurricane Georges 1998 48 9 9 Hurricane Gilbert 1988 47 10 Hurricane Cindy 2005 44 11 Hurricane Jeanne 2004 42 1 12 Hurricane Danny 1985 39 13 Tropical Storm Beryl 1994 37 14 tie Hurricane David (tie) 1979 34 14 tie Tropical Storm Bill (tie) 2003 34 16 Hurricane Ike 2008 33 17 tie Hurricane Agnes 1972 32 17 tie Hurricane Isaac 2012 32 19 Hurricane Opal 1995 31 20 tie Hurricane Allen 1980 29 20 tie Tropical Storm Lee 2011 29 1 22 Hurricane Gustav 2008 28 23 Tropical Storm Allison 2001 28 3 24 Tropical Storm Josephine 1996 27 1 25 Hurricane Lili 2002 27 26 Tropical Storm Debby 2012 25 3 27 Hurricane Charley 2004 24 1 28 Hurricane Alicia 1983 22 29 Hurricane Audrey 1957 21 30 tie Hurricane Carla (tie) 1961 20 30 tie Hurricane Gaston (tie) 2004 20 1 Tropical Cyclone Rankings for Number of Tornadoes Produced McCaul, Grazulis http://www.tornadoproject.com/alltorns/tophurricanes.htm
  42. 42. • Greatest Number of Tornadoes occurred in the Northeast Quadrant over the Coastal Bend Region. Held Record 115 Tornadoes until Hurricane Ivan Hurricane Beulah - 1967
  43. 43. Photo: Washington Times Record 127 Tornadoes! Hurricane Ivan - 2004
  44. 44.  Storm produced 35 tornadoes  10 significant (F2>) Located 150-250 miles from storm center Hurricane Allen - 1980
  45. 45.  Total of 41 tornadoes  Occurred at distances of 230-470 miles from the storm center that was near Monterrey, Mexico  F2 tornadoes in Del Rio and San Antonio Hurricane Gilbert -1988
  46. 46. Tropical Cyclone Hazard Impacts Dependence on Category of Storm (Saffir Simpson Hurricane Wind Scale) Storm Surge Flooding Tornadoes Flooding RainsDamaging Winds Not RelatedOnly Somewhat Related Not RelatedRelated although not whole story ~
  47. 47. Error Cone ~ Cone of Uncertainty What Does the Cone Tell Us • NHC Forecast of where the CENTER of the storm will be in 12, 24, 36, 48, 72, 96, 120 hours • 5 Year NHC Forecast error (2/3rds of tropical cyclone center forecasts remain in cone)
  48. 48. Error Cone ~ Cone of Uncertainty What Does the Cone NOT Tell Us • How far out the tropical storm/hurricane force winds will extend • Timing of the onset of tropical storm/hurricane force winds • How high the storm surge will be • How far out the storm surge will extend • Onset of when flooding from storm surge will begin • How much rainfall is expected • Where and how far out flooding rain is expected • When the rain will begin and end • Where tornadoes are expected • When the tornado threat may begin • 1/3rd of the time the NHC forecast goes OUT of the cone • Forecast CONFIDENCE • Range of scenarios Error Cone like the SSHWS does NOT tell the whole story!
  49. 49. Hurricane Isaac (min cat 1) 6 to 12 feet of Storm Surge; levees topped, extensive flooding Up to 20 inches of rain Case Examples & Testimonials
  50. 50. Parish President: “Worse than Katrina” (Katrina Cat 3 at landfall, Isaac barely a category 1)
  51. 51. Hurricane Isaac Makes Landfall in Louisiana – NYTimes.com August 28, 2012 Federal officials warned again and again that the storm, which killed 29 people in Haiti and the Dominican Republic, would generate high seas, intense rain and serious flooding in coastal and inland areas for days. But residents toughened by Hurricane Katrina, which tossed floating casinos across the highway, saw Isaac as more a curiosity and a nuisance than a major threat. “If it’s a 1 or a 2, most people don’t flip out,” said Claire Parker, 23. • Overreliance on category and comparison with previous storm (Katrina) • Many times people focus and make decisions based on the category alone, without digging into the details!
  52. 52. Hurricane/Superstorm Sandy: HurricaneHybrid; Another very large low category (1) storm with huge impact
  53. 53. Officials fear many won't evacuate for Hurricane Sandy USA Today, October 28th 2012 The problem is, some people in the storm's path evacuated for Hurricane Irene last year only to be met by more punishing winds and floods further inland. This year, many of them are staying put. "There are a lot of folks out there who feel if it's not a Category 3 or higher, they tend to dismiss it," says Julia Jarema of the North Carolina Division of Emergency Management. "Hurricane Sandy is a huge storm. We want them to take it seriously." • Overreliance on category and comparison with previous storm (Irene)
  54. 54. Approximately 2/3 of fatalities due to Surge and 1/3 Due to Winds Hurricane Sandy - 2012
  55. 55. Hurricane Ike: Large Category 2 Storm
  56. 56. Quotes from “Storm Surge and Certain Death: Interviews with Texas Coastal Residents Following Hurricane Ike,” Weather Climate and Society Morss and Hayden (2010) 1 2 3
  57. 57. Conveying All Threats – Not the Category • Hurricane Local Statements • Tropical Cyclone Potential Impact Graphics • Email Briefings & Social Media Posts • Storm Surge Warnings – Possibly 2014 • Better Inundation Graphics - 2015
  58. 58. Alternative to SSHWS Hurricane Local Statements from Weather Forecast Offices • Detailed forecast for each hazard (wind, rain, storm surge flooding, wind) spelled out for each county • Forecast uncertainty described • Attempt to put new and the most important information at the top of the product (no more burying the lead) • This text product can be long
  59. 59. ...WINDS... AS TROPICAL STORM ISAAC APPROACHES...SUSTAINED TROPICAL STORM FORCE WINDS ARE EXPECTED TO BEGIN THIS MORNING. HURRICANE FORCE WINDS WILL BE POSSIBLE TONIGHT. MAXIMUM WINDS ARE FORECAST TO BE IN THE 60 TO 80 MPH RANGE WITH GUSTS TO 95 MPH. ...STORM SURGE AND STORM TIDE... AS TROPICAL STORM ISAAC APPROACHES THE COAST...THERE IS AN INCREASING CHANCE FOR COMBINED STORM SURGE AND ASTRONOMICAL TIDE WATERS UP TO 12 FEET ABOVE MEAN SEA LEVEL WITHIN AREAS CLOSER TO THE COAST...RESULTING IN WORST CASE FLOOD INUNDATION OF 10 TO 12 FEET ABOVE GROUND LEVEL MAINLY IN AREAS OUTSIDE HURRICANE PROTECTION LEVEES ESPECIALLY IN ST BERNARD PARISH. STORM SURGE FLOODING SHOULD BEGIN EARLY TUESDAY MORNING AND CONTINUE THROUGHOUT TUESDAY AND TUESDAY NIGHT. ...INLAND FLOODING... A FLASH FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA. SEE LATEST FORECAST FOR LATEST INFORMATION. LISTEN FOR POSSIBLE FLOOD WARNINGS FOR YOUR LOCATION...AND BE READY TO ACT IF FLOODING RAINS OCCUR. EXPECT STORM TOTAL RAINFALL OF 8 TO 12 INCHES OF WITH LOCALLY HIGHER AMOUNTS POSSIBLE. ...TORNADOES... ISOLATED TORNADOES WILL BE POSSIBLE AS RAIN BANDS ASSOCIATED WITH TROPICAL STORM ISAAC MOVE ACROSS THE AREA TODAY AND WEDNESDAY. Hurricane Local Statement 5 am August 28th, NWS New Orleans Wind timing and magnitude Storm tide referenced to height above sea level AND height above ground level Rainfall information and flood threat described Tornado threat described
  60. 60. Alternative to SSHWS Tropical Cyclone Potential Impact Graphics • Graphical depiction of potential threat for each tropical cyclone hazard • Threat rated none, low, moderate, high, extreme with each term defined in a legend • Issued whenever watches or warnings are out for an area (48 hours prior to arrival of TS force winds) • Starting point for these graphics is derived from a set of tools that translate existing forecast guidance
  61. 61. http://www.weather.gov/tcig http://w1.weather.gov/tcig
  62. 62. WFO New Orleans Coastal Flooding Impact Graphics Definitions (Storm Surge)
  63. 63. Can Create KML Images/Google Earth
  64. 64. Can Create KML Images/Google Earth
  65. 65. Slow Moving TS, >20 inches of rain in some spots!
  66. 66. FLASH FLOOD STATEMENT NATIONAL WEATHER SERVICE TALLAHASSEE FL 1016 PM EDT MON JUN 25 2012 FLC037-077-129-260315- /O.CON.KTAE.FF.W.0016.000000T0000Z-120626T0315Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ LIBERTY FL-WAKULLA FL-FRANKLIN FL- 1016 PM EDT MON JUN 25 2012 ...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT FOR NORTHEASTERN FRANKLIN...WAKULLA AND SOUTHEASTERN LIBERTY COUNTIES... ...A FLASH FLOOD EMERGENCY CONTINUES FOR WAKULLA COUNTY... AT 1007 PM EDT...EXTREME FLASH FLOODING CONTINUES ACROSS WAKULLA COUNTY...PARTICULARLY ALONG THE SOPCHOPPY RIVER INCLUDING THE TOWN OF SOPCHOPPY. WATER HAS ALREADY ENTERED HOMES IN SOPCHOPPY AND THE SOPCHOPPY RIVER IS EXPECTED TO CREST FAR ABOVE ITS PREVIOUS RECORD CREST. THIS IS A LIFE THREATENING SITUATION AND MANY AREAS THAT HAVE NOT FLOODED IN RECENT MEMORY WILL FLOOD TONIGHT. &&
  67. 67. Conclusions • Need to dig deeper than the Saffir-Simpson Hurricane Wind Scale if we are to anticipate hurricane threats • Public education is a challenge • NWS Forecast Offices make detailed forecasts of each hazard in their Hurricane Local Statements • Tropical Cyclone Potential Impact Graphics are intended to take probability into account, represent potential outcomes that require preparation. • Hurricane Center Public Advisories are a great source of information on the larger scale • Storm surge warning coming down the pike also intended to alert people to risk of surge
  68. 68. Jason Runyen Jason.Runyen@noaa.gov 361-289-0959 Senior Forecaster - NWS Corpus Christi Thank You! Have a Safe 2013 Hurricane Season

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