Hurricane how does it occur

These clouds are just the beginning. Credit: NOAA. Meteorologists have divided the development of a tropical cyclone into four stages: Tropical disturbance, tropical depression, tropical storm, and full-fledged tropical cyclone. When the water vapor from the warm ocean condenses to form clouds, it releases its heat to the air.

The warmed air rises and is pulled into the column of clouds. Evaporation and condensation continue, building the cloud columns higher and larger. A pattern develops, with the wind circulating around a center like water going down a drain. As the moving column of air encounters more clouds, it becomes a cluster of thunderstorm clouds, called a tropical disturbance. As the thunderstorm grows higher and larger, the air at the top of the cloud column is cooling and becoming unstable.

As the heat energy is released from the cooling water vapor, the air at the top of the clouds becomes warmer, making the air pressure higher and causing winds to move outward away from the high pressure area.

This movement and warming causes pressures at the surface to drop. Then air at the surface moves toward the lower pressure area, rises, and creates more thunderstorms.

Winds in the storm cloud column spin faster and faster, whipping around in a circular motion. Hurricane Season begins June 1 and ends Nov. That means six months out of the year we need to monitor the tropics.

The peak of the hurricane season is around mid-September. That's when sea surface temps are at their warmest. But warm sea surface temperatures are only one of three key ingredients for hurricanes to form. One is sea surface temps at or above 80 degrees. The warmer the temps, the more moisture or fuel for the storm. Once a hurricane moves over land, its fuel is cut off and the storm begins to weaken. The second ingredient is a pre-existing spin or area of low pressure. The third ingredient is light vertical wind shear.

This allows the thunderstorms to grow tall and not be sheared apart by strong winds. So now it's time to talk about how hurricanes form. Hurricanes form when warm moist air over water begins to rise. The rising air is replaced by cooler air. This process continues to grow large clouds and thunderstorms. These thunderstorms continue to grow and begin to rotate thanks to earth's Coriolis Effect. The thunderstorms will rotate counterclockwise in the north hemisphere around the center which is called the eye.

The eye is an area of descending air which produces light winds and dry conditions. The strongest winds will be located just outside the eye in the eye wall. Let's talk about tropical classifications. A tropical Depression is an area of low pressure with a closed center of circulation and sustained winds less than 39mph.

A Tropical Storm is when that area of low pressure continues to deepen and has winds between mph. The whole system of clouds and wind spins and grows, fed by the ocean's heat and water evaporating from the surface. Storms that form north of the equator spin counterclockwise.

Storms south of the equator spin clockwise. This difference is because of Earth's rotation on its axis. As the storm system rotates faster and faster, an eye forms in the center.

It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye. If you could slice into a tropical cyclone, it would look something like this. The small red arrows show warm, moist air rising from the ocean's surface, and forming clouds in bands around the eye. The blue arrows show how cool, dry air sinks in the eye and between the bands of clouds. The large red arrows show the rotation of the rising bands of clouds.

When the winds in the rotating storm reach 39 mph, the storm is called a "tropical storm. Tropical cyclones usually weaken when they hit land, because they are no longer being "fed" by the energy from the warm ocean waters. However, they often move far inland, dumping many inches of rain and causing lots of wind damage before they die out completely.