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Strom (about Enviroment)
- 2. WHAT YOU NEEDTO KNOW ABOUT HURRICANES & TROPICAL CYCLONES AUG 19, 2009
- 3. TROPICAL CYCLONES Marvin Bennettand Ken Tobin (CEES/TAMIU)
- 4. OVERVIEW DEFINITIONS, CLIMATOLOGY,& HISTORY HURRICANE HAZARDS FORECAST PROCESS HURRICANE PREPAREDNESS
- 5. Tropical Cyclone Definitions TropicalCyclone is a generic term for a warm-core low pressure system that forms in the tropics or subtropics. Tropical Systems are further categorized by a difference in their wind speed.
- 6. Tropical Cyclogenesis (Formation) Tropical Disturbance with thunderstorms Distance of at least 300 miles from the equator Ocean temperatures at 80ºF or warmer Abundant moisture - low and middle part of atmosphere Weak vertical wind shear To become a tropical cyclone several ingredients are needed:
- 7. TROPICAL CYCLONES BIRTH :Nearly all tropical storms/hurricanes start out as a tropical disturbance - an area of unsettled weather in the tropics.
- 8. Tropical Storm Cyclogenesis(Formation) The conditions on the previous slide only occur close to the tropics (generally within 25o latitude) & during specific times of year! Hence hurricane season in the Atlantic Basin is defined between June 1 and November 30. The peak in hurricane season is around September 10th, which corresponds to the time when ocean water in the tropics reaches its maximum temperature.
- 9. Tropical Cyclone Definitions Tropical Depression = < 39 mph Tropical Storm = 39 mph – 73 mph Hurricane = > 74 mph Major Hurricane = > 110 mph (Cat 3 or greater) Once a distributed area becomes organized this system becomes a Tropical Cyclone. Tropical Cyclones are categorized by difference in their wind speed:
- 10. Tropical Cyclone Evolution TropicalDepression = < 39 mph
- 11. Tropical Cyclone Evolution TropicalStorm = 39 mph - 74 mph
- 12. Tropical Cyclone Evolution Hurricane= > 74 mph Hurricane Isabel’s power initially focused attention on the storm, but its size, not power, ensured it would be destructive. Surfers loved the big waves rolling into Ocean City, N.J., on Monday, but when Isabel hit on Thursday, much larger waves were hitting much of the East Coast.
- 13. Tropical Cyclone Structure •Doppler radar showing hurricane main parts: – Eye – Eyewall – Rainbands. • Counter-clockwise rotation. • In very center of the storm, air sinks, forming an "eye" that is mostly cloud-free.
- 14. FAMILY OF TROPICALCYCLONES INFRARED SATELLITE PHOTOGRAPH … AUGUST 28, 1996
- 15. Tropical Climatology • Stormsfavor the Gulf of Mexico & Western Caribbean Points of Origin -- June
- 16. Tropical Climatology • Mostactive month of the hurricane season. Points of Origin -- September
- 17. Texas Hurricanes -Galveston • Sep 8-9, 1900 • 8000+ killed • $30M damage • 20 ft. surge • Max 135 mph • Cat 4 LOUISIANA MEXICO TEXAS * Galveston Points of Origin -- September
- 18. Tropical Cyclone Hazards •Storm Surge • High Winds • Inland Flooding • Tornados
- 19. Tropical Storm/ HurricaneImpacts • Storm Surge - simply water that is pushed toward the shore by the force of the winds swirling around the storm. • Advancing surge combines with normal tides to create the hurricane storm tide - can increase the average water level 15 feet or more.
- 20. Tropical Cyclone Impacts Cameron County StormSurge From SLOSH Model
- 21. Tropical Storm/ HurricaneImpacts Heavy rains create inland flooding that results in fatalities and/or loss of property. An example is Hurricane Carla where in Jefferson County, 180 miles from the land falling storm, $17.5 million in damage occurred, with $14 million of it water damage. Rain totaled up to 19". Three to four feet of water flooded Port Arthur. Total damages from Carla estimated near $400 million.
- 22. Tropical Storm/ HurricaneImpacts • Tornadoes – Hurricane Carla had its greatest impact in Texas. – Twenty-six tornadoes were spawned – one tore apart 120 buildings and killed 6 in Galveston Hurricane Beulah spawned over 100 tornadoes
- 23. Forecast Process • Forecastsobtained by either postal zip code, city/state search, or by point & click maps • Weather Information in clear, concise format • Emphasizes local weather expertise NWS Internet Site www.srh.noaa.gov
- 24. Forecast Process • TROPICALSTORM WATCH - A tropical storm watch is issued when tropical storm conditions, including winds from 39 to 73 miles per hour (mph), pose a possible threat to a specified coastal area within 36 hours. • TROPICAL STORM WARNING - A tropical storm warning is issued when tropical storm conditions, including winds from 39 to 73 mph, are expected in a specified coastal area within 24 hours or less.
- 25. Forecast Process • HURRICANEWATCH - A hurricane watch is issued for a specified coastal area for which a hurricane or a hurricane-related hazard is a possible threat within 36 hours. • HURRICANE WARNING - A hurricane warning is issued when a hurricane with sustained winds of 74 mph or higher is expected in a specified coastal area in 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continues, even though the winds may have subsided below hurricane intensity.
- 26. Forecast Process -Graphic Product Note that the center line indicates the “average” of the forecast track. Storm can end up any where in the cone & affect areas outside of the cone The size of the cone increases as the forecast period becomes greater
- 27. Tropical Cyclone Preparedness Hypothetical Hurricane“Carly” Brownsville Landfall Source: UT Space Science Center
- 28. Tropical Cyclone Preparedness . Source:UT Space Science Center
- 29. Brownsville / SouthPadre I. Mean Sea Level Brownsville Source: UT Space Science Center
- 31. Brownsville Hurricane Carly 9/11 at1500 CDT MEOW NW at 8 MPH Surge: 17.3 Feet Source: UT Space Science Center
Editor's Notes
- #4 Tropical Cyclone Definition: A Tropical Cyclone is the general term for a cyclone originating over tropical oceans. This term encompasses tropical depressions, tropical storms, and hurricanes. On any one day, numerous synoptic-scale cloud systems appear in the tropics and subtropics. Only a limited number of these tropical disturbances develop into mature tropical cyclones.
- #6 Tropical Cyclone Definition: A Tropical cyclone is defined as any disturbance which develops in the tropics or subtropics. There are several sub-categories of tropical cyclones: defined by knowing the wind speeds within the system. Thunderstorm complex usually part of the system
- #10 Tropical Depression Definition: A Tropical Depression is a tropical cyclone with a closed wind circulation and maximum surface winds up to 34 KTs. Tropical Depression Characteristics: Cloud systems produced by tropical depressions take on a variety of forms. The shape and appearance depends both on the type of lifting mechanism initiating their convection and the vertical wind shear of the storm’s environment. Satellite identification of cyclonic rotation can be difficult. Sometimes cyclonic cloud rotation can be identified through time-lapse loops or a pinwheel cloud pattern.
- #11 Tropical Depression Definition: A Tropical Depression is a tropical cyclone with a closed wind circulation and maximum surface winds up to 34 KTs (39 mph). Tropical Depression Characteristics: Cloud systems produced by tropical depressions take on a variety of forms. The shape and appearance depends both on the type of lifting mechanism initiating their convection and the vertical wind shear of the storm’s environment. Satellite identification of cyclonic rotation can be difficult. Sometimes cyclonic cloud rotation can be identified through time-lapse loops or a pinwheel cloud pattern.
- #12 Tropical Storm Definition: A Tropical Storm is a tropical cyclone with maximum surface winds between 35 to 64 KTs. Tropical Storm Characteristics: When a tropical depression matures into a tropical storm, its cloud rotation is usually more readily identifiable. This rotation can usually be identified through time-lapse imagery or a pinwheel cloud pattern. In this example of Tropical Storm Lili, the pinwheel pattern is easily identifiable. The low pressure center of the tropical storm is located near the center of the pinwheel. As a tropical storm matures and strengthens, it modifies its immediate environment to the extent that storms in later stages of their development look much the same.
- #13 Hurricane Definition: A Hurricane is a tropical cyclone with surface winds 65 KTs and greater. Hurricane Characteristics: Common hurricanes features include: Eyes Eyewalls Central Dense Overcast (CDO) Spiral bands The more concentric and better defined these features appear, the stronger the hurricane.
- #22 When it comes to hurricanes, wind speeds do not tell the whole story. Hurricanes produce storm surges, tornadoes, and often the most deadly of all -- inland flooding. While storm surge is always a potential threat, more people have died from inland flooding in the last 30 years. Intense rainfall is not directly related to the wind speed of tropical cyclones. In fact, some of the greatest rainfall amounts occur from weaker storms that drift slowly or stall over an area. Inland flooding can be a major threat to communities hundreds of miles from the coast as intense rain falls from these huge tropical air masses. The United States has a significant hurricane problem. More than 60% of our Nation¹s population live in coastal states from Maine to Texas, Hawaii, and Puerto Rico. Hurricane Floyd (1999) brought intense rains and record flooding to the Eastern U.S. Of the 56 people who perished, 50 drowned due to inland flooding.
- #32 This Brownville with a storm sue of 17.3 feet, as projected by the UT Space Science Center. The County has over 350,000 people, with at least the same number on the Mexican side. Such an event may draw many people from the Mexican side seeking shelter in the US. As far as I know, the US does not yet have a clear policy as to whether they will stop people evacuating along hurricane routes and check their immigration status. As we saw with Katrina, a break in the levees should that occur could add to the human tragedy. Flooding upstream would also wash into the Rio Grande the numerous hazardous materials now located on the Mexican side. Information is not available from the Mexican government as to where those materials are stored, what they are stored in, or the composition. These are wind damage estimates for each county, according to the Space Science Center, with the highest being Cameron County, over $6 billion. This does not include flood damage, which are partners at PBS&J are looking at now as part of our planning process.