Friday, 12 March 2010

Atlantic Hurricane Tracking

This is a new blog that allows users to track hurricanes and tropical storms in the north Atlantic. I wanted to create a blog that would allow me to track the storms then immediately report their location by means of comment, images and charts. This has been a hobby of mine for a number of years, and I would like to share with you the knowledge of how hurricanes form and move in the great oceans.

I will keep things very simple to start then put more effort into the project as you begin to learn the basics and progress onto the intermediates. Hurricanes come in several forms, each category of hurricane being within a distinct band based on it's intensity (maximum wind speed). Hurricanes range through categories 1 to 5 where category 1 is the least intense, while category 5 is the most intense, and deadly type of hurricane.

In order for a hurricane to develop, the climatic conditions must be favorable. The winds in the upper atmosphere must be relatively weak to avoid windshear which destroys the top of the hurricane's funnel. The oceanic waters should be relatively very warm - above 25 degrees Celsius. And the ocean currents should be moving in a westerly direction.

The inital formation of a hurricane begins with stage 1 of devopment where a tropical wave generally leaves the western coast of Africa moving in a westerly direction. This wave is formed of very dry and very warm air that has transited the equatorial regions of Africa to make it's journey westwards towards the Caribbean, then onwards to the eastern seaboard of north America. As this wave moves further west it begins to pick up moisture from the surface of the ocean. The rotation of the earth then contributes to a rotational effect on the wave which applies a turning motion to it. This turning motion is anticlockwise in the northern hemisphere.

Once the wind strength of the system reaches a certain limit, the system becomes a tropical depression, which is the first stage of a system's progression to becoming a hurricane. The turning effect should be noticeable for a system in order for it to be classified by the NHC as a tropical depression. The NHC is the National Hurricane Center.

Here is a list of the stages that a hurricane goes through with the mean wind speeds:
Tropical Depression  __ winds <39 mph
Tropical Storm          __ winds 39-73 mph
Category 1 Hurricane — winds 74-95 mph (64-82 kt)
Category 2 Hurricane — winds 96-110 mph (83-95 kt)
Category 3 Hurricane — winds 111-130 mph (96-113 kt)
Category 4 Hurricane — winds 131-155 mph (114-135 kt)
Category 5 Hurricane — winds 156 mph and up (135+ kt)

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