Evolution of a Hurricane
We’ve already gone over the various stages of development that a hurricane or tropical storm goes through, but we have not looked at the process they go through during these stages. This particular process depends greatly on certain environmental conditions where it is located at a particular time.
If these conditions are right, a hurricane can develop rapidly, and go through this process like a well-oiled machine. On the other hand, when conditions aren’t favorable, then this process can be a very difficult one, or even lead to decay. Below is a closer look at the process or evolution a hurricane or tropical storm goes through from the very early stages to its maturing phases.
Early Stages of Development
The process of hurricane development, from being a mere tempest off the West Coast of Africa or off the Central American coast to a full-fledged hurricane takes about several days depending on the sea surface temperature and upper-level wind conditions since warm water is their fuel while light winds aloft allow severe thunderstorm development.
Many of the major Atlantic hurricanes (hurricanes with winds of 115 mph or greater) that develop during the course of a hurricane season, form off the Coast of Africa. That is why they are often called Cape Verde storms (for the group of islands off of West Africa). A spin or rotation develops when the air within the circulation is pulled inward toward the center.
Coupled with the Coriolis effect, which deflects the wind to the right sector of the circulation, this spin causes the developing storm to rotate counterclockwise. These storms begin to mature when they develop a closed circulation, and thunderstorms wrap around the storm’s center.
Hurricane Intensification
High winds spiral inward through bands of thunderstorms. These spiral bands are commonly known as the outflow, outer bands.
These gusty winds stir up ocean moisture, which creates thunderstorm clouds, which rise to the upper portion of the stratosphere and cool.
The storm grows as it uses ocean moisture as additional energy. Rising air near the center of the storm condenses, creating heavy downpours and releasing tremendous amounts of heat and energy, which is why these storms have such cold cloud tops.
This in turn, forces the barometric pressure in the center of the circulation, or the eye to drop at the surface, pulling in more air and strengthening the storm as the air rises to about 50,000 feet where most of it is propelled outward, making room for more rising air.
Some air sinks back into the center, warming it and creating a nearly cloud-free eye. The hurricane engine is now complete, and now the storm is mature and begins to grow into a dangerous threat.
Note: The graphics and source of this information was How Hurricanes Form page at InJersey.com’s Hurricane Watch web site.