(BigCountryHomepage.com) – This Weather Workshop kicks off our Summer Series of experiments! With the kickoff of the Atlantic Hurricane Season on June 1, it’s a sign that summer is on the way here in the northern hemisphere.
In our first Summer Weather Workshop, Meteorologist Kayleigh Thomas walks us through how to make our own hurricane in a bowl to learn about their structure!
Fill your jar or mixing bowl with water. Then take your spoon to stir the water inside of the jar or bowl in a counterclockwise motion.
You want to have the water swirling around at a good speed.
Next, while the water is still spinning remove the spoon and drop four to five drops of food coloring into the swirling water.
The rotation should be relatively contained to the center of the container for the first bit.
As the water continues to rotate, the food coloring will expand and create outer bands.
What is a hurricane?
Hurricanes are one of the most dangerous types of storms on Earth. Hurricane is actually a more specific name for these types of storms that form over the Atlantic or eastern Pacific Ocean. The generic name for these kinds of storms is a tropical cyclone. You may hear scientists use hurricane and tropical cyclone interchangeably.
This experiment allows us to see how the structure of a hurricane looks from the top. What we don’t see in this experiment is what is needed for an actual hurricane to form. We’ve said it before, but most weather phenomena have a few necessary ingredients for them to form.
For a hurricane you need:
- A large area of warm ocean water – at least 79° or warmer
- Very warm and moist rising air off the ocean surface
- An area of existing low pressure
- Light winds outside of the storm – enough wind to steer the storm but not enough to disrupt the circulation
The best way to think about how hurricanes work is to think of them like an engine. This storm “engine” requires fuel, in this case that is the warm, moist air. That is the first, and arguably most important, ingredient.
This also explains why tropical cyclones form in tropical regions where the water is much warmer.
Next ingredient is the wind. For cyclones forming in the Atlantic Ocean, winds blowing from east to west are most beneficial. When the wind blows over the warm, moist air above the ocean surface, that water begins to evaporate. Then, that water vapor rises and eventually cools down and condenses back into water droplets, forming clouds.
Meteorologists have broken down the development of a tropical cyclone into four stages: Tropical disturbance, tropical depression, tropical storm, tropical cyclone or hurricane.
Tropical disturbance – The pattern of evaporation and condensation continues and builds the cloud columns higher.
Tropical depression – With the continuation of growth for the thunderstorm, the air at the top of the system releases heat and becomes unstable. This releasing of heat energy from the cooling water vapor makes the top of the clouds become warmer.
Warmer temperatures mean higher pressure at the top of the system. That high pressure at the top pushes winds outward. With high pressure established at the top of the system, the pressure at the surface of the system drops. All the while, the clouds are continuing to build and the winds continue to pick up speed while rotating.
Once the maximum wind speed reach between 25 and 38 miles per hour, it can be called a tropical depression.
Tropical storm – To reach tropical storm strength, the winds must reach 39 miles-per-hour (MPH). At this stage, the storm gets a name.
The winds at this point begin to turn around the eye of the storm, which is the calmest part of the system. In the northern hemisphere this rotation is counterclockwise thanks to the phenomenon known as the Coriolis force.
Hurricane – Once the wind speed reaches 74 MPH, the storm is a hurricane.
Hurricanes can grow up to 50,000 feet high and 100+ miles across. The calm center of the storm, the eye, can be anywhere from five to 30 miles wide.
Once the hurricane hits land, they will weaken because they don’t have their “fuel” of warm, moist air feeding them. But that doesn’t mean hurricanes only impact people on the coast.
Hurricanes can still move far inland and dump a hefty amount of rain. The outer bands of the hurricane help spread the rainfall over a wider footprint.
How strong is a hurricane?
The Saffir-Simpson Hurricane Wind Scale is a ranking system from category one to five, based on a hurricane’s maximum sustained winds.
While hurricanes do bring other potentially deadly hazards, like storm surge, flooding, and even tornadoes, those are not taken into account for the categorical ranking.
|Category 1||74-95 mph|
|Category 2||96-110 mph|
|Category 3||111-129 mph|
|Category 4||130-156 mph|
|Category 5||157 mph or higher|
The Saffir-Simpson Hurricane Wind Scale really estimates potential property damage, according to the National Hurricane Center. All categories of hurricanes can bring extremely dangerous wind conditions. Category three through five hurricanes are classified as ‘major hurricanes.’
If you have any weather questions or experiments you want to see, send Meteorologist Kayleigh Thomas an email by clicking here. See you soon!