Hurricane- intense storm of tropical origin with sustained winds greater than 64 knots(74
mph)
Eye- area of broken clouds in the center where conditions are calm and air is rising.
Feeder Bands- bands of rain that spiral in towards the center.
Eye Wall- ring of intense thunderstorms that whirl around the storm's center.
Ingredients needed to form hurricanes:
1. Ocean water must be 80 degrees For above for sufficient evaporation to occur and water must
be about 200 ft. deep.
2. Winds at the surface must be converging (coming together).
3. Unstable atmosphere so that air rises and forms clouds.
4. Air up to 18,000 ft. must be very humid for proper development.
5. Winds blowing towards the system should be coming from nearly the same direction to
avoid tearing the storm apart(shear).
6. High pressure in the upper atmosphere to help pump away air.
The lower the air pressure at the surface, the stronger the hurricane is.
Hurricane Life Stages:
1. Tropical Waves- unorganized groups of thunderstorms develop over the ocean.
2. Tropical Disturbance- thunderstorms get organized by converging winds making them
come together and begin to have a slight circulation.
3. Tropical Depression- system then gets better organized and winds increase between 20
and 30 kts (23 to 39 mph).
4. Tropical Storm- Winds then increase to between 35 and 64 kts (39 to 73 mph).
5. Hurricane- Winds then increase about 64 kts (74 mph) and the system is then classified as a
hurricane.
Coriolis Effect- deflection of wind and ocean currents caused by the Earth's rotation.
In the Northern Hemisphere- Coriolis effect makes objects go to the right.
In the Southern Hemisphere- Coriolis effect makes objects go to the left.
Hurricanes spin counterclockwise in the northern hemisphere.
Hurricanes spin clockwise in the southern hemisphere.