Hurricanes are of great interest, at least in the Southeast United States where every fall one or more of them (on average) make landfall somewhere on the Atlantic or Gulf coast between Texas and North Carolina. Since they not infrequently do billions of dollars worth of damage and kill dozens of people (usually drowned due to flooding) it is worth taking a second to look over their Coriolis dynamics.
In the northern hemisphere, air circulates around high pressure centers in a generally clockwise direction as cool dry air ``falls'' out of them in all directions, deflecting west as it flows out south and east as it flow out north.
Air circulates around low pressure centers in a counterclockwise direction as air rushes to the center, warms, and lifts. Here the eastward deflection of north-travelling air meets the west deflection of south-travelling air and creates a whirlpool spinning opposite to the far curvature of the incoming air (often flowing in from a circulation pattern around a neighboring high pressure center).
If this circulation occurs over warm ocean water it picks up considerable water vapor and heat. The warm, wet air cools as it lifts in the central pattern of the low and precipitation occurs, releasing the energy of fusion into the rapidly expanding air as wind flowing out of the low pressure center at high altitude in the usual clockwise direction (the ``outflow'' of the storm). If the low remains over warm ocean water and no ``shear'' winds blow at high altitude across the developing eye and interfere with the outflow, a stable pattern in the storm emerges that gradually amplifies into a hurricane with a well defined ``eye'' where the air has very low pressure and no wind at all.
The details of the dynamics and energy release are only gradually being understood by virtue of intense study. An http://www.aoml.noaa.gov/hrd/tcfaq/A11.html on the Atlantic Oceanographic and Meteorological Laboratory's Hurricane http://www.aoml.noaa.gov/hrd/weather_sub/faq.html website contains a lovely description of the structure of the eye and the inflowing rain bands.
Atlantic hurricanes usually move from southeast to northwest in the southern latitudes until they hook away to the north or northeast. Often they sweep away into the north atlantic to die as mere extratropical storms without ever touching land. When they do come ashore, though, they can pack winds well over a hundred miles an hour (faster than terminal velocity and thereby enough to lift a human right off their feet or a house right off its foundations) and can drop a foot of rain in a matter of hours across tens of thousands of square miles. The latter causes massive floods that are the most common cause of loss of life in hurricanes.
Hurricanes also can form in the Gulf of Mexico, the Carribean, or even the waters of the Pacific close to Mexico. Those hurricanes tend to be highly unpredictable in their behavior as they bounce around between surrounding air pressure ridges and troughs.
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