Module 5 Airmass Stability

Yeah, we're going to talk a lot, a lot, lot of stuff today. But, uh, one of the biggest things about what we're going to be talking about is: keep in mind, while we walk through all this stuff, uh, the reality is, when it comes to the stability of of of an air mass, uh, it most likely will lead, if it's unstable, to weather that we have to deal with as pilots. Because, of course, we fly in weather. So, to understand some of the vertical motions of uh air masses, we'll talk about a few: convergence, divergence, and orography. So, if you've uh done the reading, you're familiar with orography; it's kind of cool. But, uh, we we'll show you some pictures, help you explain some stuff, and uh see how that goes.

Um, let's see. Also, uh, this is going to start to tie into uh next week's lecture on global circulation. So, uh, as we start, I'll explain it as we start to go along, and you'll see kind of the correlation between—I mean, all this stuff is connected—so it's just a matter of understanding how uh it's connected. So we'll talk about these first uh three items. So we'll start off with uh some a pretty simple graphic, uh, which is kind of nice. So, uh, on the left-hand side, you have uh low pressure that's converging, or coming together; it doesn't have anywhere to go when it gets to that middle point; it starts to go up, right? So, if you remember that thing from the Coriolis effect, where all the air was traveling towards that low-pressure area—in this case, in this example, it looks like over a desert—and so there's differential heating, right? So there was a warmer spot on the desert, causes air to start traveling up, and everything else comes in to fill that void, creating a low-pressure area, and of course that rotation from Coriolis, right? So, uh, in this particular case, uh, because we have converging air flows, uh, it has nowhere else to go.

The opposite, of course, is just the—there is—as a high-pressure area, where you have a bunch of air that's uh above it, creating a high pressure, or the the air is—that air mass is dropping or sinking into this area, and of course, just as before, uh, it hits the surface, has nowhere else to go but out, and it's still uh under the effect, just like the low was, of the uh Coriolis effect. So it starts rotating, of course, in a clockwise fashion. All right. So keep these two in mind: low pressure—clouds, storms, that kind of stuff—instability versus the high pressure—you can see clear skies. I'm looking on my window; it's looking pretty clear today, which is nice. Uh, most likely, if we looked it up—which I didn't this morning—teach weather—I didn't even look at the weather today because it was a beautiful day—and it's most likely because a higher pressure came in, and it's kind of keeping all those clouds away.

We'll look at this uh uh little picture here. Uh, in this graphic, you can see the upper upper part of the picture, similar to what I just showed you before, where the low air—or I'm sorry—the air starts to uh converge upon the middle uh where the low pressure is, and it starts to travel upwards. All right. So the biggest thing for you to remember is: where you have a low-pressure system, that air is traveling vertically up. Okay? If you can remember that, everything else is kind of the opposite, as far as like a high and stuff like that, and um it'll it'll help you remember like weather systems and stuff like that, hopefully. Uh, the other thing that you get, of course, is it doesn't always happen at the surface. So you can have, you know, like one type of air mass on the bottom, another type of air mass on the top, or you can have two air masses like coming together or catching up to the other, whatever. Uh, but whenever you have a couple of air masses that are coming together or converging uh with each other, um you know, it's because it's up in the upper uh atmosphere; it can go either way. So if you look at this, you can kind of see it'll kind of interesting weather. So, in other words, like in the upper atmosphere, you'll have a lower pressure as as the air starts to travel upwards, uh versus kind of a higher pressure as the air travels down towards the surface. So, uh, kind of interesting weather you get from that kind of stuff, and we'll talk about it as we start to go through fronts and all that kind of junk. Um, but for now, all you need to do is understand the term of convergence and what it means as air uh comes together. All right.

Uh, the other one, of course, uh which is the opposite, is divergence. So that's the outflow; so it's going the opposite direction, uh just like the uh original picture where it shows the air traveling down. So you have uh a lot of that uh air pressure pushing down uh on towards the surface, uh kind of pushing everything out. So uh you can hear it uh you know when they talk about it; they could talk about sinking air; it's the same kind of term, or it's associated with it. So it just really means higher pressure is pushing down in the atmosphere. All right. So it has nowhere to go, so it goes to the side when it's in the upper atmosphere. This is interesting. So this is kind of similar to what we get is like for inversion layers here in Southern California. So you have a high-pressure system that's above it, right? So it's kind of pushing everything down, and then you have also down below that air, you have another air mass kind of pushing upwards, or that low. So as it starting to go up, you get a formation of clouds, but the clouds don't really grow. So hopefully everybody uh understands those simple concepts: one goes in, one goes out.

So to be able to visualize it a little bit better, I have have uh this graphic, which is kind of nice because not only does it show the United States, but it shows the two different systems. Okay? So left-hand side, you could see the high; in the case of a high, we know that it's pushing down, right? So the air is traveling from the upper atmosphere down to the surface versus the low, as you can see, it's bringing air in, traveling upwards uh towards the upper atmosphere. Now, why is that important? Well, it's important because this is also another way in which air can circulate within the atmosphere, right? So you have air from the upper atmosphere traveling down towards the surface, and then it goes to the low, that pressure gradient force, right, and the little curves associated with the the Coriolis effect, and then it starts to travel back up into the atmosphere through the low. So you can see it's just kind of all moving around, which is really important to understand um as we start to look at different types of weather. So, and this this picture is uh kind of has a lot of stuff going on, right? It reminds you the direction of the air flow between a high and a low, but it also shows you something unique which I'll show on the next slide, but you can kind of visualize it a little bit here, and it might make a little bit more sense when we get to the next slide. But look at the direction at the very bottom, towards the surface, right, where the high is rotating clockwise. Okay? You can see the arrows; they kind of go all go towards the Midwest, right? So the the high's going in one direction, the low's going in the other direction; kind of meet up; that's where it starts to accelerate, but we still have that pressure gradient force, right? So from the high to the low, it's starting to curve over towards that low, and as it does, we'll see in a in in the next picture that a lot of that air that's being pulled down from the high-pressure area is coming from Canada, and of course that creates that cold front that you see with that little blue line with the the triangles on it. So it's pulling cold air down, and you can see with this low—because it's a little bit better picture than the next one—um where the low in its rotation is pulling air from the Gulf uh up. So you have cold air on one side, you have warm air on the other, warm and moist, a and then of course you're probably going to get uh a lot of weather associated with it. But you can see that the red line with the little half moons, that's a a a warm front. So you can see all the different types of air masses uh as it starts to rotate, as far as the jet stream at the very top, uh of course it's being affected uh in one way shape or form as it goes over or uh next to the the lows; has an effect; you can see it kind of bending or twisting uh in between those two systems. You'll see a trough—that's that extended low-pressure area. So as the air travels over the top and drops in towards that trough, it starts to accelerate, and as it goes through that trough and and exits or diverges, right, it starts to accelerate even faster.

To get a little bit better idea of what that looks like in a little different view, uh I have this picture. So this one shows the upper air and it shows the surface. So the upper air was what I was just describing, where the air is traveling over the top of that high and it starts to drop down; it shows it a little bit better on this one into the trough and accelerates out. You can see the barbs uh and the speed in which the air is traveling; it goes much faster during that that transition from downhill uh to diverge out the other side. But down below you can see, of course, the high and the low, which I explained; you can hopefully understand where that cold air is being drawn down from Canada and the warm air from the low is being pulled up from the Gulf. So really I just want to I want to set that in place so you guys can think about it when you start to look like at weather maps; you watch the news—news is always a bummer—but if you watch the weather part of the news, uh you'll also see you you'll be able to see pictures like this and kind of visualize where is the air coming from. So whenever you see a high or low, especially a low, think about where it's drawing its air from. And so if you if you can think about that, you can figure out if it's going to be, you know, warm and moist or something with a lot of humidity like from the Gulf, is it going to be colder from Canada, is it coming off our Coast, off the west coast, and is it pulling air in off the ocean towards us, right? So kind of think about that as you look at at at charts, uh even though we'll get in charts the second half of the semester, I just want you to start thinking that way uh whenever you look at weather going forward, which is nice.

So uh the last thing, of course, is orography. So we get this a lot here in Southern California uh and Northern California, and I'll show you the differences between the two in terms of mountain ranges and stuff like that in a sec. But first, you need to understand the concept; pretty straightforward, and we're kind of—we might be familiar with it, but just didn't know what it was or what it was officially called, and now you'll know—as the as the storms come in off the off our coast and go towards the mountains, of course they they they have to go up and over the mountains, and uh unless they're really high and they don't have to worry about that, but for the most part, when that air mass starts to rise up, it'll start to form clouds. As the clouds—as the air mass goes up—it cools off, and then eventually clouds are formed, uh and we'll explain that here in just a second how that happens, um and they typically drop most of their rain or a lot of the rain um on what's called the windward side of the mountain. So in the valley is usually a little bit more lush, and of course, as those clouds go over the top of the ridge, they go on the leeward side of of the uh mountain range, um you now get what's called—you can see a rain shadow—or in our case, what we're familiar with, of course, is the desert. So keep this in mind, that little picture, as we look at the desert; the desert is in green—probably should be brown—but it makes a more visual picture, and uh plus it shows you know the Mojave Desert, which is kind of cool. So

Um, here's the one of the big differences. So as we get um like storms coming in—more—you get more storms in Northern California than you do in Southern California; it's just it is what it is. Um, but in the case of Northern California—or in this case, you look at this map on the left-hand side, kind of in the middle and uh north of that—you see the San Joaquin Valley. The San Joaquin Valley is nice because, generally speaking, if it gets all the rain, uh it's a very fertile land, and one one of the main reasons for that is orography. As those storms come in, they hit the Sierra Nevada range and they start dumping all their rain or snow, which of course goes right back down into the valley, uh which which is the reason why San Joaquin Valley has a lot of farms on it, uh which is nice. If you look at Southern California, it's a little bit different because our mountain ranges are actually kind of west to east, right? So uh the the the mountain ranges that we have, even though we get the same effect because it is kind of surrounding—we call it the LA Basin because we're kind of surrounded uh in this flat region that we live in by all these mountains that surround it—and so we do get orography associated with it. Uh, if we look—you look out towards Palm Springs—usually last month we got quite a few of them—it kind of lessens as it as everything starts to cool off because it's less volatile—um you get the like big thunderstorms and stuff uh that form over the Palm Springs—or the San Jacinto mountains and stuff like that—um and that's because of orography; it's just pushing all that air mass up, and of course heat doesn't help either.

Um, let's see what else we got. Uh, so you can see the the big green area, of course, is the desert, which essentially is is much much drier than the other side side of the mountain range as you continue to travel over. So pretty interesting stuff. Um, you know, eventually hit another mountain range, you get the Rockies and stuff, and the whole thing—the whole process starts all over again. But in this case, it shows a few clouds, and so we need to be familiar with clouds as pilots, so we'll talk about a few of those today. Um, but we see that uh big wispy one that's at the top, uh that's called a banner cloud, just as the wind is kind of whipping around it, it starts to form and then dissipate as it goes around the other side. Similar to if you go to the air show, you're going to see that—that hopefully you'll be able to see some of this stuff happen—if there's enough moisture in the air where you get either a cone in front of the jet, which is kind of nice—it's not going supersonic, it's getting close, but it's still uh transonic—uh, but you get a cloud formation around the jet, or you can get it on the trailing edges or the leading edges of the aircraft, or could be just from the wingtip vortices, but it's kind of a similar thing where it's created either due to pressure or temperature changes that are very quick, and of course as those pressure and temperature changes change also just as quick, they dissipate. So that's why you only see that fuzzy cloud over the the jets for a very brief period of time, and it just disappears. Anyway, so as the clouds go over the top, they hit the ridge line and then they dip down in, and you can see that they dissipate down at the bottom; that's where they start to evaporate, uh mainly because of pressure differences, and then as it starts to go up uh through that little valley and it comes up on the other side, uh what you'll see is that little puffy, soft, cottony-looking cloud, right? I want you guys to kind of take a good look at that cloud because you notice it kind of stands out; there's nothing around it really except for the ridge line of the mountain itself, right? So if you ever see one of these clouds over our local mountains and you're flying a plane, you see I like that little cloud—do not fly by that cloud. It's called a rotor cloud, and the turbulence inside that rotor cloud is nasty. So you will see them if you fly to like Vegas, uh up to Mammoth, uh you know, anywhere around the mountains, there's a good chance you might be able to see something like this, uh as the wind travels up and over usually a ridge line and it will create this rotor. So rotors are bad; it's kind of like like if you go surfing a lot, it's like super bad white water, you know, that you get stuck in; you can't tell what's up—um that this these are bad. Well, like in this one, we can see the the the clouds going over the top and dissipating. Here's another shot of that, um which is kind of neat, where you have the marine layer that comes in off the coast and then it goes over the ridge line—like this would be going over towards like uh like William J Foxfield over in the desert. So as the clouds come over the top, occasionally you can see some Big Bear too, which is kind of neat, depending on which which direction the wind is blowing. But as it goes over the top, it kind of follows the contour of that ridge line—that's uh almost said Coriolis—it's the Coanda effect—you'll get this—you can see it here; you can also see it in aerodynamics as the air flows over the top of an airfoil and it wants to hug the shape of either the ridge line or the airfoil—and uh which is a kind of a neat effect. Um uh but in this case, uh of course it's it had condensed already, becoming visible moisture, and then it just evaporates as it drops over the other side. Um, but hey, if you're ever thinking about Henri Coanda, you know—know back in 1934, he was a big deal—so so we're talking about him still today; it's amazing.

So other things that have happened. So you need to to to kind of get into uh instability, you're trying to understand how that works, uh we'll have to look at a little bit of history. I know you didn't take this class for history, but here you go; here's some history. So if you guys recognize who these guys are, I'm going for your brothers; if you don't, well, uh you will know a little bit about them here in a second as we talk about what they've done in their past. So these boys kind of grew up working for their dad and his paper company, and uh of course typical of boys when they're working for their dads, they started screwing around, and while they were doing it, they decided to put—for I don't know why—but for some reason, put uh warmer air underneath little little bags or paper and found that it rose up, and they thought that was kind of interesting. So they had goofing off—bigger uh bigger designs—which is pretty crazy, and they notice it still goes up—kind of like I think they're Japanese lanterns or something like that, same idea. So of course, you know, they decided—well, bigger's better—so let's make something huge, and they made that that big huge massive balloon, of course, to show off to the world—look at what we've made—and they created the first lighter-than-air balloon, uh which is kind of neat. Um, but you know, they didn't quite understand necessarily what was happening, but that it did happen, and in this case—so kind of put on your thinking caps when we talk about this—so they went ahead—as you can tell—they put heated air inside the balloon, right, and the balloon rose. Now we know, just from talking about it, right, as air travels upwards, it starts losing temperature and expanding as…

It continues up in the atmosphere. What continues to drive that air up into the atmosphere? And of course, where it's demonstrated, uh, really well, uh, with the balloon. So it's demonstrated really well with the balloon, uh, so when you start thinking about it, one of the things that happened when they launched this balloon, uh, and in this demonstration, the balloon, of course, went up, uh, but it got to a certain altitude and all of a sudden it kind of stopped climbing, kind of hung out for a while, and then eventually kind of worked its way back down. So why do you think that the balloon would stop climbing?

Uh, because the balloon started to cool off as it went up, right? It started to match the temperature that was in the atmosphere, of the environment that surrounded the balloon. So get a better idea of what that looks like, I have this really fancy chart, uh, that came out of Glime. Put a little reference down at the bottom; it's probably different now, but uh, you can use books like this. I think ASA makes a book, um, to study for tests. This one had probably one of the better pictures that I enjoy; it makes it easy to kind of explain the concept. So with the Mulrey brothers, they decided to make this balloon; the balloon kind of would be demonstrated on the left-hand side as we start to look at this, but we'll kind of walk through this chart really quick, all these different columns, and then we'll kind of get into it and kind of relate it to what the Mulrey brothers did. Uh, the balloons down at the bottom at the surface are at 31 degrees Celsius on all three of them. The balloons up at 5,000 feet, uh, also are the same temperatures. So what are we looking at? Well, we're looking at the temperature of the environment that surrounds the balloon. So in this case, if we can either look at the balloon as a balloon or a parcel of air, so I would prefer to look at it as a parcel of air from a meteorological standpoint.

So if we were able to take that balloon, pull it up to 5,000 feet magically, let it go, what would happen to the balloon? In the left-hand side, you can see that the temperature in the environment surrounding the balloon is colder. So if the air is warmer than the colder air outside, it'll continue to rise, right? If for some reason you take that same balloon in a cold atmosphere or environment, uh, and you place it there, it will start to sink, which of course has to do with temperature and density because they're kind of related in this way, uh, to make the balloon start to come back down. So, uh, the last one, of course, course is when everything is the same, uh, which is considered its equilibrium or it's kind of where it hung, it hangs out, right? So that Mulrey brothers, the the balloon went up, then it kind of hung out for a while; that was the equilibrium part, and then of course it started to cool off inside the balloon and it started to drop back down, um, towards the Earth. So the arrows pointing up are just giving you an idea of what the buoyancy was of these objects; um, they're either neutral, descending, or ascending, and uh, it gives you a really good idea of of how the instability would be associated with the column on the left. This stable environment, like where things are going down, uh, will be in the center, and of course, stationary is just an awesome day where it just kind of hangs out and nothing really much happens.

Understanding stable versus unstable air is really important, uh, especially when you take a check ride, and I'll show you that here in a second how that works, um, but you need to understand a couple of terms, uh, which are fairly straightforward, just kind of weird terms. So adiabatic, uh, is just that process where something happens, but in this particular case, uh, energy moves, but there's no heat exchange, which is interesting, um, but what you need to know as a pilot is whether or not it's a dry adiabatic in this case a lapse rate or a wet adiabatic or moist adiabatic lapse rate. A lapse rate is something that happens to a parcel of air as it's, as an example, as it's traveling up. So as that air, air parcel or balloon, however you want to remember it, starts to travel upwards, uh, the the pressure, course, decreases, right? It starts to spread apart, and the pressure decreases and the temperature changes. Okay, so keeping the temperature in mind, right? So we, you, you memorize the 2 degrees Celsius per 1,000 feet, but in this slide you can see that there's actually a difference if the moisture that's inside that parcel of air has not condensed yet, right? As it travels upwards, its adiabatic rate is accelerated. So in other words, as it goes up, it drops 3 degrees Celsius per 1,000 feet, which is quick; um, that would be the dry adiabatic lapse rate. There's also a thing called, if you look down at the bottom, called a super adiabatic lapse rate, and this is important because you're going to see it on a test. I can say it; people still get it wrong. Hopefully, none of you guys will get it wrong, but super adiabatic rate is anything that's greater than 3° C per 1,000 feet. So you only have to remember two: the 2 degrees Celsius, which is the standard kind of FAA thing, which is the moist adiabatic rate, and then three degrees; super adiabatic is just greater than 3 degrees. So now that I pointed that out, hopefully you'll never get that wrong on the test, which I'm really hoping that would be the case. But the reason why it slows down, uh, when it changes from a dry adiabatic lapse rate at 3° C per 1,000 feet to 2° Celsius per 1,000 feet as it continues to rise is because the air or the moisture, the water vapor within that parcel of air starts to condense, and when it starts to go through that process, it slows its ascent to 2 degrees Celsius per 1,000 feet. So the FAA uses that as something that we all memorize in order for us to do kind of mental calculations when it comes to performance of the aircraft and trying to, uh, figure out what the standard atmosphere is, right? So we know like 15° C, uh, at sea level is the it's a temperature, but what is it, you know, at 7,000 feet? Well, if you know that every 1,000 feet is 2 degrees, 2 * 7 is 14, so you minus 14 from the 15, voila, right? So you'll get your standard atmosphere. So that's the reason why you have to memorize that one is so that at least you can figure, figure out, well, what's the temperature supposed to be here and compare it to whatever the temperature really is that you're flying in to figure out whether or not you're getting more performance or less performance out of aircraft. Hopefully that helps out, but here's a biggie.

So this one is something you will probably get on a check ride or get questions on tests, uh, via myself and the FAA; I know this one's on my test for sure, um, is understand the differences in the types of weather that you get from stability, whether it's unstable or stable air. All right, so an unstable air, you can see the picture kind of gnarly, uh, little big thunderstorms and stuff like that, cumulus clouds, of course. This is a cumulonimbus cloud shown in the background with the same idea, showery precipitation. So there showers intermittently or could be long, but I mean they're in areas versus consistent rain, uh, rough air, of course, you can see that's probably some pretty nasty things to fly through, and of course, good visibility underneath. So if for some reason later on as you start, you get your private, you start to fly around, uh, this is a great time of the year is to, to fly to places like Vegas and stuff because it's starting to cool off, um, but if there are thunderstorms out there that you're flying below, the the, uh, the visibility you'll get underneath thunderstorms is actually usually pretty good, and uh, if you, as long as you can guess like where the clouds start, and then so you can follow your flight plan, it's usually 7 to 9,000 feet that, uh, below the thunder you'll be able to, to fly underneath that thunderstorm clearly and to get to your destination, which is kind of neat. So good visibility in unstable air, but of course if you're in it, uh, it's going to be bouncy.

So how does this compare to stable air? Well, stable air is kind of just the opposite almost. So you still get clouds and and precipitation in stable air; this is typical like Midwest, South, uh, in in the Southeast coast, that kind of stuff, um, where they go up north like Seattle and stuff like that where they get more rainstorms or more rain, Northern California also, um, in this case, we look at the rain is more consistent. So when you know you get fronts that move in with all the clouds, they drop the moisture; it's not showery precipitation, but it's usually more consistent in stable air, um, you also get smooth air. So if you take off, uh, and a front's move through and you're just getting the rain that's associated with the front, um, you could usually climb up and fly through the clouds and it's really not too bad, which is nice. You can't see anything, you know, but the the air is is is not too shabby, so which is kind of nice, and then of course if you get below the clouds and you're doing an instrument approach, um, there's a good chance that you have fair or crappy, uh, visibility as you break out. And really important things to think about on Southern California; we get the marine layer, and a lot of times it'll be really hazy below that, uh, marine layer because the air isn't mixing with the air that's above the marine layer. So because that it's just kind of stagnant, just kind of hangs out, and it gets really hazy.

Um, let's see, so how does all this work as far as like the moisture itself, like condensing and, uh, you know, evaporating and all this kind of stuff? Uh, so let me give you a slide that will help explain that a little bit more. If you remember back in like high school science days, you might have, uh, talked about this, uh, here it is again, right? Uh, when we talk about water and water's amazing ability of being able to go from a solid to a liquid to a gas, right? And as it goes from one pro, you know, one state to another state, uh, there's terms associated with those; the basic ones just to understand that you know, ice melts, we all know that; water evaporates, right, like off the side of your cold glass that it has a bunch of condensation on it; eventually it's going to evaporate off, and then of course there's water vapor itself, which you know, the humidity might be associated with that, like in high humidity, humid areas, but there's also some science terms associated with it. So as far as melting is concerned, that's called fusion. So when ice turns into water, it goes through a fusion process. As it evaporates, it's called, uh, vaporization; so that one's probably pretty easy to remember, and of course there is sublimation that you see down at the bottom where it's showing ice going to water vapor, which is true, so that's not incorrect; that's actually proper. The the catch is, and the FAA does this every once in a while, and you'll see it, uh, not only on my tests, uh, when I talk about certain concepts, um, but you'll also see here where the FAA will use the term sublimation from ice going to water vapor directly; in other words, skipping the melting stage, right? And then they'll also use the term from water vapor into ice. Unfortunately, that is not what it's called; it's called deposition. So I'm, they don't use it, but I bring it up so, so you taking a meteorology course will actually know what that term means, and, uh, even though when it comes to the FAA, they will use the that sub term for both ways. I don't know why they do it, but you know, it is what it is.

Anyway, what does that mean to us as pilots? Well, of course, when it comes to icing in an aircraft, this is really important. So ice to water vapor is when, let's say you're flying through the clouds, uh, you're flying through an an, you know, an icing layer, you pick up ice on the wind or the, well, you could, the windshield or the leading edge of the aircraft, the airfoil, and then you break out. So now you break out, you're in the sun; it's a beautiful day; you continue flying to wherever you're going, and but you want the ice to, like, you don't want the ice on your airframe anymore, right? So as you continue to fly, you notice none of the ice melts, but it does disappear; of course, that's the sublimation part. The deposition came earlier when you were flying through the clouds where it went from a visible water V or visible moisture into, uh, ice; it formed into ice, so, directly going from water vapor to ice, an example which we'll see in a second would be frost, right? So there isn't necessarily condensation on, let's say, I'll show you a picture later of some grass; it actually goes straight to ice. So, uh, hopefully this explains it a little bit better, but if you're not quite sure about sublimation and how it works or what it looks like, um, I have this cool little science experiment; I'll show you, um, because of course we're not in class, I can't show it to you, uh, but this, it's, it's pretty cool. So see what you think about this; this explains sublimation better, uh, in a visual form [Music]. This is dry ice, which is the solid form of carbon dioxide. Carbon dioxide does not have a liquid state under normal atmospheric conditions, so it turns directly from a solid into a gas as it is warmed. As it turns into a gas, it creates a little layer of gas underneath the dry ice, and so the dry ice can slide around kind of like a hockey puck on top of a layer of air. You may have noticed that there is some liquid on the table; that liquid is water; it results from the fact that water from the atmosphere in the form of water vapor has deposited on the very, very cold dry ice. If you look very closely at the dry ice, you can see some fuzzy crystals of water vapor that are now frozen in solid form. If I pick up a piece of this dry ice and drop it on the table, some of those frozen water crystals will fall off, and then they melt on top of the table; that's where the liquid comes from. When this dry ice is dropped into a beaker of water, it very, very rapidly sublimates, turning into a gas. It's obvious that the gas is more dense than air because of the, it's sinking. On a larger scale, it's quite impressive. Here we take some leftover dry ice and dump it into a sink full of water; very large amounts of carbon dioxide gas are created, and that gas is more dense than the air around. I like how they used, uh, CO2 to be able to demonstrate it, which is nice, and uh, so you can kind of see kind of all three forms of what water goes through, and it instantly turns to ice, and then of course it melts, right, as it drops off the those little cubes, which is kind of cool.

So, uh, other things that, uh, we need to understand as far as, uh, air mass stability is understanding what the air mass is comprised of. So in order to do that, we launch weather balloons twice a day, uh, in this case, 45 minutes before the top of a particular hour, like midnight or 1200 noon; this is of course UTC. They all get released at the same time, and it allows, uh, for us to be able to receive our winds aloft reports, uh, to figure out what the winds are, what they're lo, where they're located, which direction they're going, so we can do, uh, our planning. So, uh, in order to, uh, release weather balloons, of course, they need the I, the, uh, the the scientific equipment they draw is below it; this is called a radiosonde, and it shows a couple different ones, right? So the one that's on the bottom of the balloon that the Air Force guy is holding, uh, is the same one in the lower right-hand, uh, corner; you can see kind of the anoid wafer, uh, that's kind of sticking out off the side, like, because it's been broken, slamming into the ground or whatever on the way back down, um, but it also includes other things such as a GPS tracker, a te, a tracker, uh, temperature probes and dewpoint probes, and all sorts of other good stuff are located in it. There's also another one above it, just a newer version of the same thing, of course, as technology gets better, of course, they don't need to be as big, which is kind of neat. So when they release these balloons, these things go up; it takes anywhere from 90 to 120 minutes for them to, to like do a complete flight, right? So they, they get launched, they start to go up, they get to a certain altitude where the hydrogen that's inside the balloon eventually pops, and then the the radiosonde, uh, descends back to the Earth; the parachute pops out, and then it lands, well, somewhere. So if you ever do find one of these things, you can throw it in the mail, and it'll go straight back to NASA or whoever's, whoever is releasing those, which is nice, or you can keep it as a souvenir, I guess, since we, if you pay taxes, you've already paid for that item, so, uh, I don't know what you're going to do with it because there's nothing you can really do with it, but you know, hey, you say, look what I have.

Um, it's released over a thousand sites around the world; there's about 80 in the United States, uh, that we use to, to release those, and they are tracked by air traffic control to make sure that you and I don't fly into a weather balloon, which could get, by the way, be very huge as as it climbs up in the atmosphere. All right, to get an idea of what that looks like, if you've ever wanted to follow a weather balloon to see how high does it really go, I've got a video for you. So here you go; standby for terminal [Music] count - 20 hey guys, Tori here from Overlook Horizon; it's flight day for our second flight of 2018. Overlook Horizon 11, nickname, missed, 10, 5, 4, 3, 2, 1, watch [Music] [Music] [Music] [Music] sh [Music] [Music] [Music] oh [Music]. There you go; it's kind of interesting to be able to see, uh, where a weather balloon goes, and, uh, fact you just chop down a random tree because your weather balloon got stuck up in it, and uh, I thought that was kind of interesting. I hope they ask the owner for sure, uh, but anyway, uh, the cool thing about that is understanding how high these things can go; this one went to 105,000 feet; the highest one's been, I think, as high as 155,000 feet, which is pretty crazy, uh, how high these things go, but uh, very handy as far as being able to get the information because, I mean, you think about it, you can track this weather balloon as the wind is blowing, of course, now it's, it'll be able to tell you the speed of the wind, the direction of it based on GPS, uh, as that as a balloon continues to ascend, which is all the data we need as a pilot, which is nice. So it also, in the video, you noticed that of course it went through clouds on the way up; you didn't see any snow on the way back down; you started seeing snow, which is kind of cool. You also saw as it started to come back down, you could see the ceiling or the bottom parts of the cloud, uh, that we'll be able to calculate a little bit later on, uh, in this lecture; I'll show you how to do that, uh, which is important, uh, but when I talk about the ceiling, that's what I'm talking about as the bottom half of those clouds.

Speaking of clouds, right? We're going to talk about clouds, right? So, uh, it is all related to air mass stability, of course. This is where you're going to be able to enjoy some amazing artwork that, uh, I went out of my way to draw on a whiteboard to explain all these concepts that I show you on the left-hand side of the screen, screen. So it's just a basic idea of some of the stuff we talked about at the beginning of this, this course, as we continue to, to walk through and see how everything's kind of related, um, there is the drawing, and you, you can see you get

The electromagnetic energy that comes from the Sun hits the Earth, starts to warm it up. As the surface starts to warm, it gets to a certain point where it doesn't hold that anymore, and it starts to release it back into the atmosphere. You can see the long-wave radiation that comes off; right, so that's all the infrared stuff. Like if you're walking down a street and you can see all those wavy things coming up, it looks like you're looking through water or something. Uh, that is the infrared, uh, heat that's coming up off of, uh, the ground.

Um, as it starts to continue to go up towards the upper atmosphere, pushing everything that's, uh, above it up also, uh, it will get to a point where it cools off enough, enough, uh, that it will start to condense. When it condenses, it hits that, uh, that layer, which we'll talk about here in a second, to form the clouds. Start to form, but look at the differences between when there's a high-pressure area over the, over the top where the clouds are versus a lower pressure, and I want to say just a low, but lower pressure.

So in the case of the high on the left-hand side, that air, because the clouds start to form, they'll be there kind of like a marine layer, but they won't get high, so that it creates that stability. So it allows them to form, but it keeps them down, keeps them from growing, uh, versus if there's a lower pressure, uh, on the right-hand side, it allows it to continue to kind of blast up into the atmosphere and create stuff like these thunderstorms, which we'll talk about in another lecture, which is pretty cool, uh, and gives us a whole bunch of volatile, unstable weather and stuff. So pretty straightforward, you could use this for studying to help you, just if, if you need a reminder how the stuff works.

Um, and we're going to be talking about the lifted condensation level in a minute, which is the area in which clouds will start to form. So below it is clear, then you hit the lifted condensation level, and then it starts, cloud start to form above that. So you get a little bit better visual here in a second when we start to talk about it to understand how clouds are formed. So there is a saturation level, which is that lifted condensation level I just mentioned, and it's essentially where the temperature and the dew point come together. And as soon as they meet, it creates that opportunity of the water vapor to attach itself to a particle, like dust or something in the atmosphere and create visible moisture. Visible moisture to us would be, um, fog when we're sitting on the ground, right, and you have to sit around and wait for it to burn off before you can fly, or visible moisture could be the marine layer, right. So you look up and you see the clouds, you're like, ah, I wait for this to burn off or you know, get high enough that I can, let's say, do pattern work or that kind of stuff, right.

And then, of course, being able to see some of the, the clouds as you fly, let's say to Vegas where there's thunderstorms and stuff, uh, you want to be able to know how high are those clouds, so I, I can, you know, file my flight plan so I can fly below them to get to where I want to go. And we'll talk about how to do that, uh, in, in just a few slides. So what I want you to be able to understand is how a cloud forms, which is really important because just having water vapor alone is not going to create the cloud. Just having the temperature, dew point, uh, alone without another component will not form a cloud. It's kind of interesting how this works.

So I got a video from somebody you might be familiar with to explain the concept, uh, in a more visual way. So you know how a cloud is formed in a bottle. This one, what we're gonna do is we're gonna add some air and pressurize it, so the what happens, you're effectively ever so slightly warming the air inside, and then that warmth will cause the liquid, uh, droplets which are stuck to the particles of smoke to, uh, go back into solution as a vapor. Three, two, one. Kind of so, not much happened. So we will reproduce this demonstration by adding some dust, uh, similar in principle to the dust you get, uh, when you, uh, live on a prairie or if you're on the open ocean where wind blows salt from the sea into the air and water evaporates leaving tiny crystals of salt. So we'll blow the matches out and drop them in the bottle. So it looks like there's hardly any smoke at all. Furthermore, you might figure the smoke, smoke you do see is kind of in a train or in a plume that's right behind the matches, but watch what happens when we pressurize it, uh, and then, uh, remove the pressure. When you take the pressure off, the air inside will spread out, the molecules are spread out, the energy, the kinetic energy of the molecules will be spread out, and they will then effectively cool off. When they cool off, the water vapor in there will turn to a liquid and attach itself to the dust or the smoke. Three, two, one. Cl. It's not magic, my friends, it's science.

Now that we understand where clouds come from, right, and how they need a particle of some kind, right, so they need something to attach to to become visible, uh, to us as a cloud. So one of the things that, uh, can happen, of course, with moisture or the water vapor is it can create dew. So in this, there we go, there's my grass example, uh, where condensation, so is the air, the, the water vapor that surrounds the grass, of course, it touches the grass, the grass is cooler than the atmosphere surrounding it, and because of that, as it cools off quickly, it forms, uh, into a liquid, which is nice, or condenses anyway. So other things that can happen, uh, besides grass is a solid surface, like in this case a wing. So in an airfoil or anything else that could, you know, could be well, anything, usually you'll see it like on the top of your hood, could be if you're in a colder environment on your windshield, that kind of stuff, uh, when water vapor instead of turning into liquid will go straight from gas into a crystal form, and in this case, it would be frost. The important thing for you as a pilot to understand is frost is very dangerous on an airplane because it messes with that boundary layer. So it's a little different boundary layer than what I've talked about in the past, of course, in the environment we're talking about 2,000 feet when it comes to an air mass and stuff like that, but on a jet or an aircraft, the boundary layer is about the thickness of like a playing card, uh, it's very small. So frost has a tendency to stick up into that boundary layer, which is not good because it'll disrupt the air flow as it travels over the airfoil. So if you do get frost on your, on your aircraft, please take it off, uh, however you're going to do it, uh, I do talk about in aerodynamics how to remove it, um, there's the, the simple ones, of course, just stick the airplane out in the sun, like this one, right, heated hangers and, uh, deicing fluid, that kind of stuff. So, uh, but that would be deposition, right, going from water vapor directly into ice or water vapor directly into water where it gets deposited on something, um, to form the liquid. Oh, this is cool. So, uh, my example here on this last point was, uh, if you had a pint of ice cream, right, so you take that pint of ice cream because you've had a bad day, you rip that thing open, you're like, I'm mowing into this thing, and you grab your spoon, you start eating it, and then you get about halfway through and you're like, h, that's, that's a lot, so I can't finish it. But of course, while you're eating it, it started to melt a little bit, right? So you put the top back on, you save it for later, and, uh, and let's say a week later, right, you're like, oh, another bad day, where's my ice cream or whatever, so you pull it out, you pull out the top, you look inside, and there's all these crystals there, that's the, the white dew, so it's freezer burn or whatever else you want to call it, uh, but that's what it comes from when water or moisture has had a chance to, to melt just ever so slightly and then refreeze right away. So instead of forming ice, it forms crystals, uh, in the term in, and it's like white dew. So the solution for that, of course, is to eat the entire pint of ice cream all at the same time, and then you don't have to worry about it ever again.

So other things that we can talk about, uh, when it comes to water vapor would be fog, uh, this is kind of bad as far as work concerned, uh, and if it's really thick, it can stop even commercial airliners from taking off, right. So essentially fog is just a cloud on the ground, it's, it's that simple. So, um, as the temperature dew points come together at the surface, uh, it would form visible moisture as, uh, in this case where heat is conducted away and it starts to cool it off and create fog. So there are different types of fog that you need to know. So the first one would be advection fog. This is probably one of the more classic ways to look at advection fog as it kind of rolls in in San Francisco as, uh, that warm air mass is going over the cold water as it travels in, uh, towards the bay, it starts to condense and cause this really thick fog that can, if it's bad enough, start covering the entire Bay and San Francisco International Airport and make your commute horrible, which is happened a bunch of times for me. So you just got to plan for it ahead of time to avoid that whole problem. Other things that, uh, fog does, of course, is we have radiation fog. Radiation fog is usually caused by, like in this case, like a mountain area where you have, uh, it's really cold in that valley on like a moonless night, and it starts to condense all that water vapor that's inside, uh, that valley or in, in that valley and creating clouds. So that'd be radiation fog. Other ways that you can see fog would be ground fog, which you might be familiar with, uh, it's kind of that, uh, coming up to Halloween, right, so it's kind of that creepy look, you know, where it's kind of foggy, but it's not foggy because it's kind of translucent. Um, this shows a football field, which is kind of a classic thing, could be anything, uh, and some big wide area where you'd be able to see some of that fog. A lot of times you'll see it by, uh, like lower areas, uh, surrounding water and stuff like that, um, but ground fog, uh, there is a definition to it, and of course, uh, I list that as less than 20 feet. So in other words, it's not thick like you see the same as the advection or the radiation fog down below it, but it's just kind of doesn't go very high. All right, so three different types of fog that you'll need to be familiar with. Just remember advection has a horizontal movement to it as it comes in, radiation fog hangs out, ground fog hangs out, and eventually, of course, it burns off, uh, occasionally though, the, the radiation fog, it, it might not burn off if the temperatures don't get low enough, or I'm sorry, high enough, uh, to burn it off.

Um, other ways that clouds can form, of course, is something that we're familiar with or we've seen, uh, which are contrails, pretty interesting. So as that air travels through the engine, gets like super hot, and then, of course, as it's blasted out through the other end of the engine, uh, that super hot air expands very, very quickly, condenses, and forms, uh, directly into these little crystals, which are clouds, which eventually you can see the temperatures I've listed down below, uh, of what temperatures you'll normally see, uh, contrails appear, and of course, it has everything to do with the humidity that's up there. You got to have enough of it to start to create the contrails. Others, of course, would be the aerodynamic contrails, which I kind of talked about before, uh, about temperature and pressure going over the top, in this case, of the wing as it's pulling a bunch of G's, uh, and then the wingtip vortices that come off, uh, the wingtips of every aircraft, uh, this is a very efficient one, so they're very thin versus like a 757 which has these massive ones, uh, the older 747, same thing. All right. Other things that we have, uh, besides contrails, is chemtrails. I don't know if there's any believers out there, uh, for chemtrails, but here's the switch that we had in our CRJ when we flew it, uh, to be able to flip them on and off. Then there are other ways in which you can see chemtrails up here in the sky, uh, the only true chemtrail that you can see in this picture is in the upper right-hand side. Can anybody guess what that is? So if for some reason you do have an emergency when you're flying some of the really bigger jets like 747s or something that carries a whole bunch of fuel, um, occasionally if something happens like you have an engine out on a twin-engine plane, um, uh, you would need to, most likely, dump some of that fuel because you're too heavy to land. So you can take off, but you can't land unless you get rid of some of that fuel, and that's one of the ways they can do it, of course, down below we can see a couple different pictures, uh, which are kind of cool of some contrails, uh, which is on the lower left-hand side, uh, showing that bomber being refueled, and of course, the kind of aircraft that does the refueling is in the lower right-hand side, uh, where it shows the boom that sticks out, uh, that would attach itself to the aircraft, and then that's just kind of leftover fuel, uh, as it, as it detaches. Um, so I don't know if anybody, that picture, just, just so you know, just in case, is actually photoshopped in the upper left-hand side, it's not real. So chemtrails are, I don't want to burst anybody's bubble, but, uh, they're, they're not real. Sorry.

All right. Cloud height definitions as we move on and, uh, take a look at cloud height definitions, uh, especially for, uh, student pilots or new private pilots, you need to be able to remember what the references are to the clouds. So in this case, I highlighted in blue, cloud heights are AGL or above the ground, and that's super, super important because, because you, you can get cloud heights from different places. All right, I'll give you an example. You're in John Wayne Airport, you're ready to take off, you get the weather from either ADIS or METAR or whatever, right, and it gives you, let's say a ceiling, and let's say the ceiling is, we'll make it easy, make it 2,000 feet, right. So if you were standing on the airport and you just got the weather and the weather says ceiling is 2,000 feet, you know from where you're standing if you look up, the bottom of those clouds is at 2,000 feet above the ground. But this is where you have to have like your critical thinking skills, right. So what elevation are you standing at? Ah, so remember when it talks about cloud height, where you're standing is irrelevant because it's going to be measured from wherever you're, you're at, whether you're in Denver or John Wayne Airport, straight up to the bottom of the clouds. So it's above ground level. The only reason why I brought up the other thing, like what elevation you're at, right, is when you get a pilot report, and with a pilot report, remember anybody that is flying an aircraft, which is what you're doing when you give a pilot report, where are they getting their altitude information from? Their altimeter, and their altimeter is based on mean sea level. So I only bring that up to make sure that you know the difference between AGL or above the ground, right, and MSL, which is mean sea level, which is your reference from the, like sea level up to whatever altitude you're at, right. And if all your pressures measured the same, of course, in your CMS window, if everything, are pressure at the station and in your aircraft are the same, your true altitude would be the same also as MSL. So other things you need to know, uh, in this, if you have any questions, throw them out there, uh, as far as cloud heights is a couple little definitions. So mist, we get that a lot in Southern California, is usually less than 50 feet AGL, um, but we can have, you can have mist that goes up a little bit higher, uh, fog. This is really important, 5/8 visibility. You think, well, why 5/8? It's just kind of a weird number, all right. So the FAA does all visibilities in eights, even though I don't look at stuff and think, oh, I'm about 5/8 of the way to that stop, so, right, no, but as far as the FAA is concerned, this is the way they judge visibility. So remember, remember whenever you see, uh, visibility stated, I'll give you a chart here in a second to study from, but you see it stated from the FAA, it's going to be in eights. My big point here is do not reduce any fraction that you might see, like 2/8 or 4/8, like I, you're probably in your head you're automatically trying to reduce that fraction, don't do it. In the FAA's eyes, they just think of like this big pie, it's cut in eights, and that's the only way you can state it is in eights. So just like some of the stuff that I've brought up before, I say it a million times, and hopefully you won't get it wrong on the exam on mine or the FAA. So remember, everything's in eights, don't reduce it, don't, don't take the bait of the reduced fraction in the answer. All right. Other ways, uh, that you can tell visibility is vertical visibility. Vertical visibility you'll get this a lot, especially on heavy, like between fog and the marine layer and stuff like that, um, where you look up, uh, and you don't really see, you can't see the ceiling, you can't see like the bottom of the clouds, but it's kind of, it's still kind of foggy, is right. So you look up and you're like, I can't really tell. In this case, there's, most of the time, there's lasers that will point up towards the clouds, it'll be able to clear and figure out where the ceiling is, and it will give you that number and in the METAR as a vertical visibility, uh, like, uh, 200 feet, 100 feet, 50 feet, whatever it is, um, when there's an undefined ceiling or you can't tell, the machine can, or at least it gives its best guess, is probably the best way to put it anyway. Big, big takeaways, remember the difference between AGL and MSL. AGL, everything you get from your METARS and AWOSes and stuff like that is above the ground. Okay, moving on, uh, cloud height definitions, uh, continued. We have, well, there's, oh, I have the pictures, I should, I guess I should have thrown those up, I wasn't looking at the rest of my slides. So here's some examples of like layers. This is kind of cool in a Brazilian airliner as we were popping through different layers as we continue to climb. Um, other things we have, I have a picture of, where is it, there it is, as like a, like a marine layer is something similar to a marine layer rolling in over the top of a runway. So if you're coming in, of course, you'd want to get in there quickly, but remember usually, uh, the, the weather equipment is somewhere around the middle and, uh, it might start telling you you need to do an instrument approach in it, so just, just make sure you let them know that you can see it visually, uh, all the parts of the airport that you need in order to land your aircraft. Anyway, so that gives you an example, uh, this does happen every once in a while at John Wayne Airport or up in San Francisco, uh, it's kind of cool, uh, especially if you're flying like in an airline or you're on an instrument approach, uh, where it doesn't matter because you're flying on instruments and you get to see views like this, uh, when you're going down to minimums, uh, to get into the runway. In this case, you get the approach lighting system and just past those, those bars you can see, or you see the little red terminating bars, which

Is considered part of the runway itself, uh, which is kind of cool. So, three different views of different types of weather, uh, that you need to be aware of. So, uh, what I meant to say earlier was, here are the abbreviations that you're going to be fam—you need to get familiar with, right? So this is where all those eights take place, right? And this is—I put that in there because this is the way the FAA wants you to know, right? So, sky clear is—well, that's a no-brainer, right? It's just clear. Clear—well, that's also clear, but it's defined as—well, there's no clouds below 12,000 ft. I don't make the rules; this is just the FAA.

So the next couple are few and scattered, uh, that's—so, uh, the way I remember that is, it goes one to two for few; it goes three to four for scattered. So it makes it easy to remember the eights: part one, two, three, four, uh, and then you would think the next one, if you follow the pattern, right, would be five—blank—we won't even say it, but it's not—why? Because they need to leave one extra one for the overcast, right? So, so it's one, two, three, four, five, seven, and then eight, all right? So hopefully that'll help you remember if you start to go through the test and you're like, "How—what is, you know, what's few?" If they ask you that ridiculous question—but they might—um, it's better that you understand what it looks like when you're flying. But hey, sometimes they want you to memorize this stuff, so it's in blue, so get comfortable with it.

Um, can anybody tell me on this—on these abbreviations—which two are considered a ceiling? Correct, broken and overcast. I will show you pictures here in—in just a bit, showing you the difference between the two visually and, uh, the reason why they're considered a ceiling, which is not listed on the slide, by the way. A ceiling is defined as something that you can't get through as a VFR pilot in order to transition through that—whatever the obscuration is, right? So in this case, we're thinking about clouds, and if you can't get—stay 500 feet below or 1,000 feet above—or this is the important one—2,000 feet to the sides—if you can't find a hole that matches those numbers, you can't go through those clouds and need to make sure you have to have an instrument rating to be able to pop up, which is super cool to be able to do that IFR, because you do that a lot in Southern California; it makes life a lot easier. Um, but if you're flying VFR and you come in into, let's say, the LA Basin and the marine layers rolled in, you can't get down through those clouds to land, and you might have to go—like, to the desert or someplace where the marine layer isn't, uh, to be able to land your aircraft. Uh, or in an emergency, you talk to ATC and you tell them, it's like, "I'm like, getting down to reserves and I need to descend below the clouds for landing," and they will help you do that, which is kind of nice, uh, because nobody wants anybody to—to crash because it gives them a bad day. So just remember those uh descriptors and their definitions, as far as like 1/8, 2/8, that kind of stuff. Remember, do not reduce the fractions.

All right, now here's the big deal: you want to be able to calculate uh the bases of the clouds. So I will show you how to do this; I will give it to you in three different ways. The reason why is because the first two—the FAA wants you to know—the last one is the one you'll probably stick in your back pocket, use every time. So we'll start off with kind of the worst-case scenario where you'll get the temperature in Fahrenheit, which rarely happens at all, but to understand how this works before we kind of get into the Fahrenheit thing, um, remember that our cloud heights are AGL, right—above the ground—and you're trying to figure out what that is. Um, to get a cloud, of course, at, you know, to form, we need the temperature and the dewpoint to come together, and when they do come together, wherever that may be—whether it's on the ground or up in the air—it's called the lifted condensation level. Of course, when it's fog, well, there is no—it's just fog, right? But anything above—excuse me—above the ground at forms it would be the lifted condensation L—not that you'll probably see that on a test somewhere for sure. So anyway, looking at this now, we need to be able to figure out—well, I want to calculate it because I'm going to go fly today; I want to fly below the clouds because it's, you know, it's—there's a ceiling, right, that I can't get through, so I need to be able to fly below them and—and do it safely at the proper altitude. So let me show you how to do that uh with Fahrenheit, which we rarely get. The only time you'll probably use Fahrenheit is if, for some reason, you're in the middle of nowhere and there's no weather reporting and all you have is, you know, let's say, the temperature probe in your aircraft, right? And so you look at the temperature and you just—now you can start to calculate stuff, right? But uh, so you know, you need to understand Fahrenheit in order to do this calculation, mainly for the FAA. To do that, the big thing for you to remember is the number 4.4; the rest of them—it's—they're all the same; the only difference is that denominator. So, temperature and dewpoint difference uh divided by 4.4 times a thousand will give you your number. So first you need to be able to get the temperature if it's in Fahrenheit; uh, you probably won't get that in a METAR, but I'm going to use a METAR as an example of a weather reporting. You'll most likely get it off of your—if it's in Fahrenheit—from your aircraft itself or some other way to be able to measure the temperature. All right, so the example I use is John Wayne, and I just selected a METAR, and there you go, right? So we walk through the METARs, which we'll get in the second half of the semester—you see a bunch of numbers—see the winds, visibilities, and stuff—uh, and then eventually we get to the temperatures, and the dewpoint temperature and dewpoint are always selected next to each other, typically with a slash in between them when you write it down—when you're getting a METAR to write down, you know, all the weather information—that's typically how you write it. So kind of get comfortable with that. Uh, so it shows the temperature on the left-hand side and on the right-hand side uh is 63. So the slash you see does not mean divide; the slash is just separating the temperature—the environmental temperature and the dewpoint temperature. All right, so we need to get the difference between the two, right? Right. So in order to determine that—86 minus 63—we can see it's just kind of basic math—got 23—and then we throw that into the actual formula, and we come up with 5227. So it's like pretty cool. Now we know what the bottoms of the clouds are, and now we can file 4500, 3500—whatever you're going to fly—to make sure you stay below the clouds and get to where you want to go, right?

All right, so the next way to calculate it, which is what you'll normally do, is with Celsius, because all of our weather comes in the form of Celsius, which makes life a lot easier. So whether you get a METAR, the ATIS, whatever, uh, you will get the temperatures in the same way as far as—as—as Celsius. The difference here is the denominator, which is 2.5. So 4.4 and 2.5—those are—if you were to try and remember something—those are the two numbers; uh, otherwise, the—the how you calculate it's all the same, right? So the temperature dewpoint difference—uh, first you need to find the temperature and the dewpoint; this is how it will be listed uh on the METAR, so it's easy to just pull it straight off—and then we'll go ahead and do that simple math problem again: 30 minus 17 gives us 13, and then we just plug it in, right? So the end result is 5200 feet. So there's only a 27-foot difference; who cares? That's close enough uh for what we need it for uh because we're not flying at either one of those altitudes anyway. So now we can start our planning. So remember Fahrenheit and Celsius are the official ways to figure out what the ceilings are, right? So how do we do it like—where we actually want to remember how to do it? And it's this one—this is cool. So this technique—just so you know, there's some clout behind it—is actually done by meteorologists—people that like live and breathe this stuff, right? This is where I got the calculation from, and I found it reading—like, I read a bunch of weather books; it's—I geek out on it sometimes. So I'm reading it and I'm like, "No way! It's like, can't be that easy," and I started calculating stuff out, and then I went back and I did my Fahrenheit, you know, just the ones I just showed you, and I did—I'm like, "Oh my God, this is—this is crazy." So temperature dewpoint difference, right? We already know where to get those—times 400. So I'll just blast right through this: there's all your information that you need; there's your difference, which is 13 degrees Cel—which we saw when we looked at the previous example—and then look what happens: boom, 5200 feet! It's like super easy. So if you need to remember something in the future about how to calculate wherever the um the ceilings are—which, believe me, does come in handy—um, just remember 400, right? The temperature dewpoint difference times 400—done! Which is cool. Anyway, all right, what's next? So that's the math—hurts my brain—so we'll just get into pictures.

So here's an F-33 I was flying, uh, well, just a random day off the—off the wing; you can see the uh the island of Catalina, and then in the background, of course, above it, you can see the altocirrus cloud. So alto is a word that means kind of midlevel, so it could be like 6,500 uh up to any like 16,500 or 18,000 ft, uh, just depends on which reference you're using. Uh, there's a variety of them; uh, personally, it's—you know, you need to understand the concept behind it instead of the exact altitudes, but at least you have a ballpark idea; it's kind of midlevel, right? So altocirrus—pretty cool looking—usually when warm fronts move through and stuff. Um, there's—here's another picture—driving up to Big Bear; the marine layer came in, hit all the way to the side of the San Bernardino Mountains. So I took this picture and, uh, you can see two different types of clouds. So you have the stratus layer which is below it, which is that marine layer, and then the altostratus which is above it, uh, which is reflecting some of the sun as it's—as starting to set, which is kind of neat. So stratus level uh clouds will be between like uh the surface or the ground up to like 6,500 feet. All right.

Other ones we have—this was on a bike ride; I thought it was a cool picture—where you can see more stratus clouds because they were lower, um, uh, but they're just kind of—stratus are just—they're just flat, uh, which is kind of neat looking. And so uh others with altocumulus—cumulus being—think cottony, fluffy, that kind of stuff—alto being midlevel and then kind of fluffy-looking clouds. So here's kind of a front-looking thing uh as it's continuing—as I was driving up a hill—these are—these were like 6,500 to 18,000 ft—is another term for mid-level clouds, but remember to kind of break the word in half to kind of figure it out: alto being midlevel and cumulus being the shape that you're looking at. Um, others we have—here's broken cumulus; there's that F-33 again—fun planes to fly if you ever get a chance to fly one of those—um, but it has—what I've done here is I've shown you what broken looks like. So broken means, of course, there are gaps. So if you look closely, you can see little blue gaps, and as you fly underneath this one, uh, there's actually more little gaps in between the clouds, but it's just not enough space for you to kind of, you know, get through. The scattered cumulus in the foreground, of course, you can get around that; that's like super easy. Cirrus being like way, way up there—those are kind of crystallized. So you fly through those—let's say you're flying a jet, which is probably where you need to be to be able to fly through these types of clouds—really cool looking; it shimmers and sparkles, that kind of stuff—a lot of—of fun. Uh, others—other examples—here's more cirrus clouds up at the top uh that you'd be able to fly through, uh, and then of course you have cumulus clouds below, showing as the cloud—you know—this air starts to rise—the unstable part, right—where the clouds are versus the stable side, which is the blue side—so where the—the clearing is in between the clouds. So there's kind of both in—in that convective current uh right there, showing the cumulus cloud. So those are kind of fair-weather cumulus if you want to know what those are called.

Um, one other picture would be uh scattered, broken, and scattered, uh, so you get an idea; you'll just have to slowly start to get comfortable with how to describe stuff, especially if you're going to give a pilot report. Sometimes you'll—you'll get that—ATC will ask you, you know, "What are the clouds look like?" Uh, and then you'll be able to do that, which is nice because it's good for whoever's on the ground—maybe someone who might have less experience than you that's going on a flight—you know—that could be very, very helpful to that individual. So think about that of why you would want to give ATC kind of an update if you have something like this, which is cool. Um, other bigger clouds that uh we're going to be talking about in another lecture—this is a cumulonimbus cloud or a thunderstorm cloud. It also has—because of the moisture in this—in this air—this is—well, it says easyJet on this jet, so this is uh in Europe, uh, but there's altocumulus up way up above, uh, which is kind of nice, and they're kind of scattered all over the place. You can see more thunderstorms in the background with this one—see the big puffy uh components of it—and then we have—back in the United States in Arizona—we have this supercell. Supercells are massive; we'll talk about that definitely when we get into thunderstorms because these are ones you want to give a huge berth to, and when you start seeing some of the videos I'm going to show on thunderstorms, you'll realize how important it is to stay the heck away from these bad boys. So uh pretty big—cool picture because that's—you know—I was—my son was playing baseball and seeing all the planes in the background, which is kind of cool at the same time; it was cool. Anyway, other things as far as clouds are concerned—different types of clouds—here's an example of a mountain wave cloud. So you can get them from, of course, our Sierras, as the winds are moving from the west to the east, and you can get some really big ones, right? And in this case, this—probably like going to Denver—oh, it's—we're at uh 380, so we're flight level—we're at 38,000 feet, and when we saw these and uh I thought it would be a great picture, which is kind of neat. Um, but I also—it's—it's—it's also a video, right? And so we'll see—as we talk about it—see if you can see—goes through video—if you guys saw that or not; it's kind of cool. Big Sky country, so you know—so there's other traffic out there, even though you usually don't see it, um, but remember you can also get this same type of cloud formation like in the Midwest or like flying over like Tennessee or places, you know, where the—they have what they call mountains—they're not really mountains, you know, they go to like 4,000 feet, but whatever—um, but you can get the same kind of thing because there's enough moisture in the Midwest or as you go towards the East Coast um where you can get these kind of clouds, but they're just like really low, but same—same formation. I think earlier we saw it when we were looking at the weather balloon while it was going up; you could see clouds like that; that was kind of cool.

So I'm going to go ahead and leave you with this last video as motivation to continue on, if any of you are going to be commercial pilots for an airline, uh, to give you an example of what it's like when you're flying through the clouds to a landing at what's called a CAT II or Category 2 uh approach. Uh, it's a precision instrument approach where the captain and the—the—the—the flight officer work together in tandem in order to land the aircraft. In this case, when you watch the video, the FO or the flight officer on the right seat is actually flying the aircraft all the way almost to the ground. This is a CRJ-200, which is allowed to go to about 50 feet off the ground, which, if you think about it, that's—that's pretty low—pretty crazy. The captain's part in a CAT II approach is to only looking outside the aircraft—not at the instruments—as they continue to fly in for the sole purpose of seeing the airport and landing the aircraft; that's the captain's job. So the flight officer flies it to the runway; the captain lands the aircraft. If, for some reason, you don't see the runway, the flight officer who's flying the aircraft will immediately do a go-around—no options—you just do it—anyway—and uh which is—is highly practiced to get certified for it—and uh you just do a go-around, come back around, or go somewhere else. So you'll see in this video, you'll see the uh the flight officer flying the aircraft on the right seat, and then eventually when the captain sees the airport and he's ready to land, he will either tap or bump the—the hand of the flight officer, who will raise his—like his hands up, which essentially means—this is why you have to get certified for it—that he's telling the captain—"Your controls"—and the captain at 50 ft—or in this case, I think it's more like 150—will take over the controls of the aircraft and land the plane. Pretty crazy stuff! It's a little different from the way you train as a private pilot, uh, but that's the reason why you have to be certified because there's a lot of trust going on right there. So here's the video; hope you like it. [Music] Stabilize 500 [Music] [Music] Minimums 50, 40, 30, 20, 10. You! You done it before! Something TCE [Music] All right, there you go; there's your motivation to continue on; there's reasons for it; it's pretty cool. Uh, sims feel pretty real when you're in them and uh because you sweat just like you do when you—when you actually do this flight. So I've done uh quite a few CAT IIs and uh they're always exhilarating is probably the best way to put it. All right. Uh, I'm going to leave you guys with a couple of things. So there's going to be two METARs that I'm going to leave you with; we're not going to really talk about them too much; this is more or less for you to study. You'll see the METAR listed at the top in blue just to highlight the text in this particular case, and what I've done is I've created a plain language readout for uh the—um—for the METAR. So each one of those components—just to give you a heads up—to—you can start reading uh uh these uh METARs ahead of time to start getting familiar because if you are a pilot, you're probably familiar with it; if you're not, or you're working on it, you need to know these METARs, period. I mean, if you're going to continue flying—doesn't matter if you're just going to be a private—or you're going to go through and become an ATP and fly for the airlines—you still need to know how to read these uh really well. So practice now uh and you'll be just fine. Um, down at the bottom I did put a link in there for you, so if you want to start getting random METARs first, do your best when you bring up some of these random METARs to try...

And read it in raw form, like you see highlighted in blue. Get practiced at reading those. Um, if you can't figure it out, go ahead and cut that out and then paste it into this, into that link down below. There's other decoders out there if you want to use a different coder; I don't care. So, but in this case, this is a pretty good one, uh, because it actually can decode some of the uh, the detailed stuff.

Um, anyway, uh, that's the one for John Wayne. There is an additional one for, uh, in this case, uh, was it uh, Nacadish? Is the is the the name of the airport. Uh, same thing, except the difference here is, remember we talked about the temperature dewpoint meeting, right? So, so the temperature dew points, if we look at this, we can see the temperatures are 11° and 11°, so they are matching. But if you look carefully, go all the way down almost to the bottom, it says the ceiling, right, which is either broken, right, or overcast. In this case, it's broken 600. It's not fog. You would think that the temperature dew points meet, right? It should create fog. So there's got to be a reason for that, and that reason, the answer to that is, if you go back up to the top in that blue highlighted area, the very last thing in that second line begins with a T. So your job to figure out why the uh, the clouds are not fog, but they're actual clouds with a ceiling as defined. The answer lies in that those numbers after the T. So your job, according to look those up and to see if you can figure out uh, what it is about the temperature and dewpoint that make it 600 overcast and not fog.

So I'll leave you with that. Go ahead and pull that off; you'll be proud that you did. And uh, we'll just kind of hold, you know, leave you with this picture of Big Bear.