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Tracking Hurricanes Saturday, July 03, 2004 Storms called tropical cyclones are intense low pressure cells surrounded by circular winds moving in a counter clockwise direction. They form over warm tropical water and gain strength over time until they either hit land ("make landfall") or move over cooler waters. Depending upon their wind speed they may be classified as tropical depressions (wind speed less than 34 knots), tropical storms (from 34 to 64 knots), or hurricanes (above 64 knots). (The terms apply to the Western hemisphere, they are called typhoons in other areas.) Many of the early season Gulf Coast storms, did not give much warning. However, most tropical cyclones, particularly those that strike the East Coast of the U. S., spend a week or more slowly moving accross the Atlantic.Living on the Southeast Atlantic Coast, I spend late summer and early fall worrying about these storms. Typically, tropical depressions start in the East Atlantic and move west towards the U. S. Coast. Most take from one to two weeks from the time a disturbance forms off the coast of Africa until a hurricane makes land fall on the Atlantic coast. As the storm progresses west, it picks up strength, changing from a tropical depression to a tropical storm (receiving a name) and then to a hurricane. Meanwhile, back on the East Coast, many of us are waiting. Every six hours we plot the coordinates on our hurricane maps while speculating about the odds of being hit. Now there are there are resources on the web to help the storm tracking and speculation. One site that helps is operated by the Tropical Prediction Center of the National Centers for Environmental Prediction, part of the National Oceanic and Atmospheric Administration's National Weather Service (www.nhc.noaa.gov). That site provides information about both Atlantic storms that may threaten those of us on the East coast, and the Eastern Pacific storms off the West coast of the US. In addition to the actual text of the advisory, usually issued every six hours, the site provides the forecast of the storm movement for the next 72 hours. (These predictions are often very accurate, but are also often very inaccurate. However, much more information is given in a discussion that is issued along with the advisory and the forecast. Another site is the tropical weather section of the Intellicast.com (www.intellicast.com/StormCenter/). Use the Tropical drop down link from the bar near the top). This page list all current tropical storms (tropical depressions, tropical storms, and hurricanes) in the Atlantic and Pacific regions. For each storm a link will display a map showing the past track and the official prediction. Links will also display the same forecasts and discussion as the official National Weather Service site (above). Another aid to storm tracking is not a web site but a shareware computer program called Tracking The Eye, or TTE.Available fromwww.gencode.com, the program runs on Windows 95/98/NT/ME/2000/XP. A trial version is free; the registered version costs $24.95. The program displays a map of the Atlantic or Pacific (selected by a menu option). Storm coordinates can be entered manually or downloaded from the internet through TTE. The current location of the storm and the track of the storm are displayed on the map. (Downloading will require registration and payment of the $24.95 fee). Data for each location, whether entered manually or downloaded, include the coordinates, storm direction and speed, maximum wind speed, and barometric pressure, is stored on your hard disk. Also on your hard disk is the data from all storms from 1900 to the present. The current storm, any previous storm you entered or downloaded, or any of the past storms in the data base may be displayed. In determining my own prediction of whether a storm will strike my location and the expected time to landfall. I often like to call up previous storms that did hit my location, compare the track to the current storm, and also determine how long the past storm took to reach landfall. These online tools won’t prevent hurricanes or lessen their damage, but they can make the waiting and wondering easier. |