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Hurricanes help distribute global energy by moving heat from tropics to higher latitudes. They form between 5 to 20 degrees latitude, mainly in the North Pacific, affecting the U.S. after forming in the Atlantic, Caribbean, or Gulf. Formation requires warm, deep ocean water and converging winds, leading to unstable warm air rising due to low pressure. The circulation in northern hemisphere is counterclockwise, with the eye wall having the strongest winds and rainfall. Learn more about hurricanes and storm surge in the provided video link.
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Hurricanes help distribute global energy… • Move heat from tropics to higher latitudes • Like El Niῆo in Pacific
Where can they form? • 5 to 20 degrees latitude • Most in North Pacific! • Hurricanes that affect U.S. begin in Atlantic, Caribbean, or Gulf • Move east to west in trade winds
Needed for formation… • Warm, deep ocean water • Converging winds at surface • Unstable warm air rises • Low pressure at center
FYI…Lowest pressure systems… • Wilma (2005) 882 mbar • Gilbert (1988) 888 mbar • Unnamed (1935) 892 mbar • Rita (2005) 895 mbar • Allen (1980) 899 mbar • Katrina (2005) 902 mbar • “Normal” atmospheric pressure is 1000 mbars at sea level
Needed for formation… • Humid air at high altitudes • Vapor condenses releasing energy • Pre-existing winds same direction, altitude, speed • Upper atmosphere high-pressure pumps air up and away
In the northern hemisphere… • Rising air moves counterclockwise surrounding the storm • Eye wall – greatest wind speed and heaviest rainfall • Bermuda High steers storms
Video • http://video.nationalgeographic.com/video/101-videos/hurricanes-101