Hurricane Characteristics

Hurricanes and Typhoons:
Derivation of the terms: The words Hurricane and Typhoon describe tropical cyclones with maximum sustained speeds of at lead 75 mph.

Hurricane from the Wed Indian word huracan meaning "big wind'. Describes Atlantic and East Pacific storms

Typhoon, form the Chinese word taifun meanings “great wind”, describes 'West Pacific storms

Circulation systems are alternately producing and resulting from circulating high and low pressure differences between the equator and poles.

Central low pressure with higher surrounding pressure
Characterized by low-level convergence and ascension of air masses

Central high pressure with lower surrounding pressure.
Characterized by low-level divergence and subsiding air masses

Cyclones are fueled by warm moist air
As this air raises it condenses releasing the Went: heat stored within it
Extremely moist air is needed to produce and sustain tropical storms
Only very warm air is capable of transporting the moisture required
For this reason these storms are only formed over water with temperatures 80 degrees and higher
Air spirals inward toward the center in an intense convection current

 -move within the large scale air mass in which they are embedded
 -upon formation movement is usually east to west in lower latitudes
 -upon landfall usually take a more northerly direction
 -once in contact with the higher latitudes its track becomes more eastward
 -may remain stationary for some time
 -Move within the large-scale air mass in which they are imbedded

Structure- The eye
 the most calm region of the storm
pressure is lowest in this cloud free region
 900-950 mb
 6-60 miles

The Eye wall
Rotates counterclockwise at maximum velocity
Typical upper end wind speeds are 180 mph