Storm Development
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Step 1 Tropical Wave: "bump" or disruption of normal tropical easterly flow. Associated turning of wind causes low-level convergence of air; which helps with falling pressure and enhanced showers. |
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Step 2 This can evolve into a Tropical Depression, which is a closed circulation of air in the low levels. This in turn increases convergence and pressure falls, and wind speeds increase in a Catch-22 effect (i.e. the stronger the wind blows the greater the convergence, the quicker the pressure falls... so the stronger the wind, etc.). |
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Step 3 Once sustained winds reach 39 mph in the closed circulation a Tropical Storm is named. Usually there are at least 2 closed isobars of 4 mb increments around the center. If atmospheric conditions remain correct the system will evolve into a... |
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Step 4 Hurricane. There is usually a difference in pressure of at least 0.60 inches of mercury between the center and surrounding pressure field, with the greatest change near the center (eyewall). It is this great difference in pressure, which sometimes can be as great as 2.95 inches of mercury, that causes the wind to be so strong. |
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Step 5 A mature hurricane is a well-oiled meteorological machine, but disruption of the processes that drive the storm (i.e. interaction with land or colder air feeding in) will begin to destroy the storm, and the disintegration of a hurricane can often be quick and dramatic. |
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Saffir-Simpson hurricane storm rating scale
Category |
Wind (mph) |
What you can expect | |
1 |
74-95 |
Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal road flooding and minor pier damage. Example: Hurricane Erin (1995) | |
2 |
96-110 |
Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of center. Small Craft in unprotected anchorages break moorings. Examples: Hurricane Bertha (1996), Frances, Jeanne (2004) |
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3 |
111-130 |
Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet ASL may be flooded inland 8 miles or more. Example: Hurricane Opal (1995), Hurricane Fran (1996), Ivan (2004) | |
4 |
131-155 |
More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet ASL may be flooded requiring massive evacuation of residential areas inland as far as 6 miles. Example: Hurricane Charley (2004) | |
5 |
over 155 |
Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet ASL and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required. Examples: Hurricane Camille (1969), Andrew (1992) |
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Storm Names |
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2008 |
2009 |
2010 |
2011 |
Arthur |
Ana |
Alex |
Arlene |
Bertha |
Bill |
Bonnie |
Bret |
Cristobal |
Claudette |
Colin |
Cindy |
Dolly |
Danny |
Danielle |
Don |
Edouard |
Erika |
Earl |
Emily |
Fay |
Fred |
Fiona |
Franklin |
Gustav |
Grace |
Gaston |
Gert |
Hanna |
Henri |
Hermine |
Harvey |
Ike |
Ida |
Igor |
Irene |
Josephine |
Joaquin |
Julia |
Jose |
Kyle |
Kate |
Karl |
Katia |
Laura |
Larry |
Lisa |
Lee |
Marco |
Mindy |
Matthew |
Maria |
Nana |
Nicholas |
Nicole |
Nate |
Omar |
Odette |
Otto |
Ophelia |
Paloma |
Peter |
Paula |
Philippe |
Rene |
Rose |
Richard |
Rina |
Sally |
Sam |
Shary |
Sean |
Teddy |
Teresa |
Tomas |
Tammy |
Vicky |
Victor |
Virginie |
Vince |
Wilfred |
Wanda |
Walter |
Whitney |
Here is a good link if you want to know more about How and Why Tropical Weather happens. http://www.physicalgeography.net/fundamentals/7u.html
Source: http://www.accuweather.com
Staff who work in this area:
Portelos-Rometo, Maria Ed.D. - Extension Agent II, Family and Consumer Sciences
King, Mary- Program Specialist, Family and Consumer Sciences
