The origin of hurricanes and predictability of hurricane tracks

Authors Avatar by astroawel2 (student)

The origin of hurricanes and predictability of hurricane tracks

Low pressure systems form at mid latitude temperate zones as a result of the convergence of warm and cold air masses. Low pressure systems generally form over the polar front where the polar maritime air (a cold air mass) and tropical maritime air (a warm air mass) meet. Air currents in this area within the Northern Hemisphere will flow counter-clockwise due to the rotation of the earth and surface friction. Air flows accumulate at the centre of the system, and the warm air rises because it is less dense, leading to low pressure at the surface. It contains more moisture than the polar maritime air and as a result, when it ascends, it condenses and produces clouds and rain. Cirrus type clouds are the first clouds that are usually created at this point.

A circulation of air rotates in an anticlockwise motion due to the coriolis effect. The tropical maritime air swirls around the polar front, the system matures and eventually a warm and cold front is created. At the warm front, the warm air rises over the cold air, the cirrus clouds develop to be cirrostratus, altostratus and nimbostratus clouds which eventually will lead to heavy rain because of the condensation of the warm air. Towards the edge of the warm front, conditions are more stable and pressure stops decreasing as much. No longer is there so much condensation and therefore there is less rain.

Polar maritime air is fast, dense, and strong. Eventually the air pushes in and forces the warm air off the ground, creating instability. The pressure increases, as the air ascends rapidly, cumulonimbus clouds form bringing in heavy rain and storms. The cold front consists of heavier and denser air and displaces the warmer and lighter air, because of this, it moves faster than the warm front and it will ultimately catch up with it. Warm air is forced off the ground by the cold air, and once this happens, an occlusion is created. Uniform air begins to fill the gap between the warm front and the cold front and this is where the low pressure system begins to die away.

Join now!

At tropical latitudes, if sea surface temperatures are above 27 degrees c, then the low pressure system will grow. If the conditions are right, tropical thunderstorms may develop to become a hurricane. Low pressure systems often begin to rotate around a central area of low pressure. This is known as a tropical depression, if the depression increases in intensity so that winds reach at least 39 mph, it's categorised as a tropical storm. If wind speeds reach and average of 74 mph, it known as tropical cyclone or hurricane.

Hurricanes/ tropical cyclones mainly develop in the region between 10 and 20 degrees North ...

This is a preview of the whole essay