 Let's talk about the most devastating, energetic, and crazy atmospheric phenomena that occurs on planet Earth. And that would be the hurricane, the typhoon, and the tropical cyclone. Now first of all, what's the difference between the hurricane, the typhoon, and the tropical cyclone? Nothing. They're the same thing. They just occur in different parts of the world. So if we're talking about a hurricane, hurricanes occur here along the East Pacific, and they occur here along the North Atlantic. If we're talking about typhoons, typhoons are occurring here along the West Pacific. And finally, if we're talking about tropical cyclones, tropical cyclones are occurring here within the Indian Ocean and here along the South Pacific. You know, if you take a look at the map, you'll notice that I didn't put any big circles or demarcations on the South Atlantic. And there's a reason for that that we'll talk about soon. But the question becomes, do any major atmospheric events like a hurricane, typhoon, or tropical cyclone occur along the South Atlantic? And the answer is yes, it can, but it's pretty rare. But if anything does happen here along the South Atlantic, we would also call that a tropical cyclone. So what we want to do now is spend a few moments and talk about a few things. Number one, how does a hurricane form? Specifically, we want to take a look at these guys here in the North Atlantic and how they flow here to Middle America. Two, we want to talk about the major energy source of a hurricane. What is feeding it? There is so much energy housed within one of these storms that you could literally feed Canada for a full year with energy consumption. Three, we want to talk about what eventually kills a hurricane. What makes it die out? If you take a look at Jupiter, Jupiter has a storm on it called the Great Red Spot. And the Great Red Spot in Jupiter has been in existence for over 300 years. It is a hurricane like storm. So why on Jupiter does the storm perpetually exist? Whereas here on planet Earth, the storm eventually will die out. All right, so sit back and let's get started. I've got my picture of the world. And on this picture of the world, I'm going to draw in the intertropical convergent zone. If you'll recall, the intertropical convergent zone is a low pressure system. And it's called the intertropical convergent zone because the east of the trade winds from the southern hemisphere and the east of the trade winds from the northern hemisphere converge together. Hence the name intertropical convergent zone. When the air from the two east of the trade winds collide together, the air has nowhere to go but up. And so this feeds into the low pressure system of the intertropical convergent zone. Now if you'll recall from prior discussion, and if you haven't seen the prior discussion, then please check out some of the other videos that I've done specifically on adiabatic processes. But in prior videos, we talked about how air lifts up into the sky. And if air lifts up into the sky, then the air will expand, reach what's called the dew point temperature. It's an adiabatic expansion process or adiabatic cooling process. This is how we're going to get cloud cover and precipitation. So lifting air up into the sky can create weather. So here along the intertropical convergent zone, which is a low pressure system, we have weather. So if you look here in Africa, we're going to find ourselves with a lot of tropical events like thunderstorms. If you go here toward Indonesia and the Philippines, you're going to get a lot of thunderstorm events. If you go here to the Amazonia, we're going to get a lot of thunderstorm events as well. So anywhere along this low pressure system of the intertropical convergent zone, we will get weather. Now let's say we want to make a hurricane. One of the things that we can do to make a hurricane is take these storms here that are developing over Africa and push them into the Atlantic with the Easterly trade winds. And if we push them over the Atlantic with the Easterly trade winds, we have an opportunity to grow those storms even bigger. Well, how's that going to work? Well, the water here is going to be nice and warm and toasty. And we're talking about surface temperatures of water that's over 27 degrees centigrade, which is around 81 degrees Fahrenheit. That temperature water is going to have a lot of evaporation. There's going to be a tremendous amount of latent heat stored in the water. The water itself has absorbed energy from the surrounding air. The water then evaporates. It lifts up into the sky and it can feed the storm. So if we have water and a lot of it that's 27 degrees centigrade or warmer, we have the ability to feed these storms. Let's stop here for a second because we need to explore something that I just said a little bit further. I just said something called latent heat. And I talked about evaporation and I talked about energy in the water feeding the storm. So let me stop here talking about the hurricane itself. Let's talk about the concept of latent heat of evaporation and latent heat of condensation. Then after that, let's get back to this discussion. So let's talk about latent heat. Latent literally means hidden. So when we talk about latent heat, we're talking about hidden heat. Now, what exactly does that mean? Well, let's say that we have a parcel of H2O liquid. So we've got liquid water. And let's say we add heat to our liquid water. As we add heat to the liquid water, the liquid water is going to start to evaporate and turn into H2O gas. Now, if I stuck a thermometer right here and if I try to measure the temperature change of the H2O, I'm not going to see any temperature change. The water is absorbing heat, but the temperature is not increasing until all of the liquid has evaporated into the gaseous form. So that's why it's called a latent heat process. It's a hidden heat transfer. However, I will see a temperature change in the air because here the air is losing heat as the heat is being absorbed into the liquid molecule. So here's our latent heat of evaporation. So again, in latent heat evaporation, we are taking heat energy from the surrounding air. We're purging it into the H2O. The H2O is evaporating as it lifts up into the sky. So this evaporated H2O is filling the sky. And when it fills the sky, it's literally filling the sky with energy that the H2O stole from the surrounding air. So if I have water with a temperature of 27 degrees centigrade or about 81 degrees Fahrenheit, that's enough energy absorbed by the liquid to increase the temperature to that point, which leads to evaporation. And enough evaporation to lift up into the sky to really feed the storm with a tremendous amount of energy. Now what happens when that H2O gas gets into the atmosphere? Well, eventually it's going to run into air, which is cooler. And when it runs into air, which is cooler, it's actually going to exchange the heat with it. And so my H2O gas molecules are going to release heat back into the surrounding air. When it does that, the air itself is going to heat up. And the H2O vapor is going to turn back into H2O liquid. And now we have latent heat of condensation. So in the latent heat of condensation process, the H2O molecule is releasing heat energy back into the air. But in the latent heat of evaporation process, latent heat is being removed from the air, or excuse me, heat is being removed from the air and is being pushed and purged into the storm itself. This is the energy which is feeding the hurricane. And as long as that storm is over water, which is 27 degrees centigrade or 81 degrees Fahrenheit, it will continually get enough latent heat, excuse me, it will continually get enough latent heat to continually feed it. The winds will get even stronger. And as it moves with the trade winds and it approaches land, it can go from a cat one to cat two to category three all the way up to category five, if indeed enough energy exists within that storm. Now, oftentimes, you'll see a storm that just stalls. So a storm will literally stall on top of very warm water that usually trade winds won't push it. And if it stalls and if it just sits on this really warm water, it'll get bigger and bigger and bigger because all of this latent heat energy is going to continually feed the storm itself. Now, let's take a look at this map again. So if we have a lot of thunderstorms, and if we do have a lot of thunderstorms that move here toward the East Atlantic, and then these storms go over incredibly unstable air, then what we can get now is the potential to make a tropical storm. And if we keep feeding this tropical storm with more and more energy, then we can develop a hurricane. Now, in what instances would a hurricane not develop? Well, if the water temperature here is not greater or equal to 27 degrees centigrade, it's not going to happen because there simply is not going to be enough energy in the system to feed the storm. If we have these storms going south, it's probably not going to happen either because the water here in the South Atlantic is generally speaking lower than 27 degrees centigrade. So it definitely takes an environmental condition which is suited for hurricane development. Now, let's say that we develop the storm. And if we develop a hurricane here, it'll first start out as a tropical storm. Then inevitably, if it gets enough energy, it can turn into a hurricane. It reaches a hurricane status if the winds are greater or equal to 74 miles per hour. If it's less than 74 miles per hour, it's not considered a hurricane. If it's 74 or greater, then we're considered a hurricane. So let's say that we have a hurricane and it flows with the easterly trade winds and this nice warm water current here going across the Atlantic. This storm now has some options. It might flow this way with the Gulf Stream. It might flow this way with the easterly trade winds. It might flow this way which is going to be a combination of the winds and the Gulf Stream. So this whole area of South, the United States and Central America really has the potential of being affected by a hurricane. Okay, now as long as the storm is over water, which is 27 degrees centigrade or warmer, it will continually exist. However, the second the storm hits land, the winds will start to slow down because the land is going to create friction. In addition to that, when the storm goes over land and no longer is getting fed by its source of energy, which is the latent heat coming from the evaporation of water. If we have a storm that moves with the Gulf Stream and goes northbound toward the North Atlantic, the water appears cold. So the second that this storm hits the cold water, it will start to dissipate as well. Typically speaking, a hurricane can last anywhere from one to two weeks. Big issues occur though when the hurricane stalls and this can definitely happen. You can have a storm that's flowing this way and instead of moving with the Gulf Stream or instead of moving all the way over with the trade winds, it might just stall. And if it stalls there and if it's continually sitting over very warm water and continually getting fed by this warm water, the storm will get bigger and stronger. And we can move from a Category 1, which is 74 to 95 miles an hour, to a Category 2, which is 96 to 110 miles an hour. If we grab enough energy and if the winds get even stronger, we can get Category 3, 111 to 129 miles an hour, to a Category 4, which is 130 to 156 miles an hour to finally a Category 5 event where winds in this storm are over 157 miles per hour. That's amazing. So this is what we see when we talk about these storms. We can start them here along the West African region. We can flow the storm this way. It'll begin to dissipate when it hits land or when it hits cold water. Let me ask a question. If we take a look here along the Eastern Pacific, we don't see a whole lot of hurricane events occurring. We see some, but we don't see a lot. And the question is why? And the answer is here, along the Western flow, we have the nice cold California current coming from Alaska. And this water is cold. And because this water is cold, any tropical event that would be pushing northbound along the equatorial zone here is going to get pushed down because of that cold water. So very rarely, if you're here in the Gulf of Mexico, will you see a hurricane type event. It'll occur, but not nearly as frequently as the storms that are occurring along here. So earlier I had asked, or I didn't really ask a question, I made a statement about Jupiter. I said the great red spot on Jupiter has lasted for over 300 years. And the question is why? Well, if we take a look at what dissipates a storm here on planet Earth, we know cold water does it because when you have the cold water, then you don't have that latent heat energy to feed the system. In addition to that, if our storm hits land, we're no longer over the source of energy. And in addition to that, we've got greater friction to slow this storm down. So if we take those two variables and we say, okay, well, how can we apply that to Jupiter without knowing anything about the planet? We can surmise that Jupiter is going to probably be a homogeneous surface. Meaning you're not going to get a whole bunch of temperature variation on the surface of that planet, nor are you going to get like a bunch of land versus a bunch of water. The surface itself is going to be homogeneous. If Earth had a homogeneous surface, if we were all water, and if the surface was always 27 degrees centigrade or warmer, then we would have some crazy weather on planet Earth because of that homogeneous system. Okay, just something to think about. That is it. Thank you very much, and I'll see you the next time.