The winds in a hurricane blow counterclockwise and angle slightly inward toward the center (eye), with an increase in wind speed as they approach the eye. This results in the most destructive wind forces occurring at the outer fringes of the eye wall. In the right quadrant of the storm (with respect to the heading), winds blow onshore. In the left quadrant, winds blow offshore. Figure 3 illustrates the inward flow of air and the rising clouds that form at the eye wall. Winds are strongest in the area slightly outside of the eye wall. The eye of a hurricane, which can range between 10 and 30 miles in diameter, contains air which is sinking slightly. This produces light and variable winds and partly cloudy skies within the eye itself.

A tropical cyclone is closed circulation (a complete loop) with cyclonic circulation (circulates in counterclockwise direction in the Northern Hemisphere). Low pressure and bad weather characterize cyclonic circulation. Normal sea level pressure, with good weather, ranges from 1015 to 1030 millabars (Mb) measured with a barometer. However in a hurricane, the pressures can range from 980 Mb to under 920 mbs. Hurricanes are low pressure areas resulting from cyclonic circulating air; normally, the lower the pressure, the more severe the storm. Table 3 is a list of the lowest central pressures that have been found in hurricanes in the Atlantic Ocean, Gulf of Mexico, and the Caribbean.