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How do hurricanes form?

How do hurricanes form?
Hurricane Eta
Posted at 2:30 PM, May 20, 2021
and last updated 2021-06-08 07:35:33-04

WEATHER QUESTION:
"Hi my name is Lily and I'm in second grade at Gulf Elementary School and my question is how are hurricanes made?"

EXPLANATION:
Most (not all) tropical systems start off of the Northern Coast of Africa near Cape Verde. The combination between Northern Africa's warm/dry air and Southern Africa's cool/humid air helps create the African Easterly Jet.

African easterly jet
The African easterly jet is where the wind is easterly and comes from the temperature contrast between the Sahara Desert and the Gulf of Guinea.

The easterly wind helps the warm Atlantic water rise into the atmosphere eventually forming thunderstorms. Tropical systems use warm water as fuel to grow and strengthen, but typically the water needs to be at least 80°F for this to happen.

As this process continues to repeat, the wind helps the storms to rotate and move west through the Atlantic. This would be considered a tropical disturbance.

The winds in the storm start whirling around in a circular motion helping the pressure to drop at the surface. Once the wind is between 25 to 38 mph, it is now considered a tropical depression.

If the conditions are right, the winds can start to blow faster and begin twisting and turning around the eye. Once the wind speed reaches 39 mph, the storm is now called a tropical storm and it receives a name.

Once the wind speeds reach 74 mph it is now considered a hurricane. Hurricanes are divided into five different categories depending on their wind speed also known as the Saffir–Simpson scale.