1. Terminology Tropical disturbance - cluster of thunderstorms, weak pressure gradients, no real rotation Tropical depression - at least one closed isobar, winds less than 39 mph Tropical storm - a depression with winds stronger than 39-73 mph Hurricane - winds stronger than 74 mph

3. Anita (September 1977) in central Gulf of Mexico

5. Notice the apparent guidance by the Azore High A Suggestive Overview

6. SST and Tropical Systems

7. A weather system for which a tropical cyclone forecast center (NHC, CPHC, or JTWC) is interested in collecting specialized data sets and/or running model guidance. Once a system has been designated as an invest, data collection and processing is initiated on a number of sites (eg. Naval Research Laboratory, U. Wisc. Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). Designation as an invest does not correspond to any particular l likelihood of development of the system into a tropical cyclone. “Invest”

8. Saffir-Simpson Scale -1 Tropical Storm 39-73 mph Hurricanes: Category 1 74-95 mph Minor damage to buildings; damage to unanchored mobile homes, signs; some coastal flooding and minor pier damage. Category 2 96-110 mph Some damage to building roofs, doors and considerable damage to mobile homes; flooding, damaged piers, small unprotected craft may break moorings, some trees blown down. (See text p 157)

9. Category 3 111-130 mph Damage to small residences and utility buildings. large trees blown down. Mobile homes destroyed. flooding near coast destroys smaller structures, larger structures damaged by floating debris. - Examples: Keith 2000, Fran 1996, Opal 1995 Category 4 131-155 mph Some complete roof structure failure on small residences; major erosion of beach areas; Terrain may be flooded well inland. - Examples: Hugo 1989 and Donna 1960 Category 5 156 mph and up Complete roof failure on many residences and industrial buildings; some complete building failures; small utility buildings blown over or away; flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required. - Examples: Katrina, Andrew(FL) 1992, Camille 1969 Saffir-Simpson Scale (cont.)

10. Surge

11. Saffir-Simpson Scale (Summary)

12. Highest activity: NH western tropical Pacific Lowest activity: SH Atlantic Global Hurricane Tracks 1995-2005

13. Hurricanes around the globe. Global “Hurricane Seasons”

14. Atlantic: TS & Hurricanes 1851-2004 (1325)

15. North Atlantic Climatology

16. 10 Average Cumulative Number/Yr AtlanticEastern Pacific (www.nhc.noaa.gov/pastprofile.shtml)

17. Vertical Shear Over Atlantic JuneSept OctAug

18. Atlantic: Shear and SST AugustSeptember

19. Named=yellow; hurricanes=green; cat 3 or greater = red Atlantic TS & Hurricanes 1851-2004

20. Prevailing Tracks

21. 250mb850mb July Surface Temp

22. August

23. September

24. October

25. November

27. Hurricane Strikes 1926-2005

28. Western Gulf

29. Eastern Gulf

30. “Return Period”

31. Scales of Motion

32. Scales of Motion (2)

34. Structure (Mature) extratropical tropical

35. “Life Cycles” Midlatitude Cyclone