Formation
Hurricanes that hit the United States form off of the coast of Africa in the low latitudes. For a hurricane to form there are a few key ingredients that need to be present. First the temperature of the ocean needs to be at least 80 degrees Fahrenheit in the upper 200 feet. Second the air must be unstabel (warm and humid) and finally the upper-level winds should be weak and blowing in the same direction as the developing storm is moving.
Source: http://www.windows.ucar.edu/earth/images/hurricane_formation_jpg_image.html
Before a storm becomes a hurricane there are stages that it goes through. First the storm starts off as a tropical disturbance. A tropical disturbance is when a low pressure zone draws in an unorganized group of thunderstroms with weak surface winds. Then the storm moves on to become a tropical depression. A tropical depression is when the surface winds strengthen and start to flow around and into the center of the storm. At this stage the storm receives a number to identify it. Next the storm becomes a tropical storm. The convering warm air meets in the center and starts to move upward. The rising moist air cools and releases large amounts of latent heat. The heat warms the surrounding air causing stronger updrafts that also increases the amount of warm, moist air flowing upward from below and wind speeds are above 39 mph. Once wind speeds are over 74 mph the storm is finally classified as a hurricane. Once a storm becomes a hurricane it can be one of five- categories.
Saffir-Simpson Hurricane Damage Scale
| Category | Storm Surge (feet) | Wind Speeds |
| Category 1 | 4-5 | 74-95 mph |
| Category 2 | 6-8 | 96-110 mph |
| Category 3 | 9-12 | 111-130 mph |
| Category 4 | 13-18 | 131-155 mph |
| Category 5 | over 18 | greater than 155mph |
The eye of the hurricane if formed by winds traveling to the center of the hurricane. As the amount of fast wind increases it is difficult for it to reach the center of the hurricane, thus forming the eye. Inside the eye the cool air sinks and as the air sinks it becomes warm and picks up moisture. The eye wall is the area of winds spiraling upwards and contains the strongest winds in the hurricane.