Speaker 1: Welcome to tech Stuff, a production from iHeartRadio. Hey there,
Speaker 1: and welcome to tech Stuff. I'm your host, Jonathan Strickland.
Speaker 1: I'm an executive producer with iHeartRadio. And how the tech
Speaker 1: are you? It is time for another classic episode of
Speaker 1: tech Stuff. This episode that you're about to hear originally
Speaker 1: published on April twentieth, twenty sixteen. Huh four twenty But no,
Speaker 1: this has nothing to do with anything you know, blazy. No,
Speaker 1: this has to do with weather technology. In fact, it's
Speaker 1: called Weather Tech Part one, and that tells you what
Speaker 1: next week's classic episode will be. So sit back and
Speaker 1: enjoy WeatherTech Part one from April twentieth, twenty sixteen. Today
Speaker 1: we're gonna talk about weather because of a listener request.
Speaker 1: This comes from Dress Sayan and dree I am so
Speaker 1: sorry if I mispronounced your name. I actually asked Dreese
Speaker 1: how to pronounce this name, and I can only hope
Speaker 1: I got close. But here's what Dreas had to say. Hey,
Speaker 1: I just wanted to ask Slash request something about the podcast.
Speaker 1: See a while back, I had a conversation with my dad.
Speaker 1: He commented how amazing it was these days. He can
Speaker 1: just check a website that will pretty accurately tell him
Speaker 1: whether it's going to rain in the next few hours.
Speaker 1: And where I said that, it doesn't seem like that's
Speaker 1: amazing progress to me. After all, when he was a
Speaker 1: kid in the sixties, they would report if it would
Speaker 1: rain the next day, and now it's just that we've
Speaker 1: got it down to a few hours instead of twenty
Speaker 1: four hours ahead. He laughed and said the weather report
Speaker 1: back then was pretty much a joke. Anyway, this gave
Speaker 1: me a lot to think about, and it seemed like
Speaker 1: something to learn about from the Tech Stuff podcast, because,
Speaker 1: to be honest, I have no clue how weather is
Speaker 1: accurately predicted. It's just always been there for me. So
Speaker 1: we're gonna talk about weather forecasting, meteorology, the technology used
Speaker 1: to make predictions, what those predictions actually mean. We're going
Speaker 1: to break all that down. There will probably be at
Speaker 1: least one or two references to how weather report. Weather
Speaker 1: reports are still largely the work of some estimations and
Speaker 1: best guesses, because, as it turns out, whether it's incredibly complicated,
Speaker 1: but hopefully by the end of it, you'll have a
Speaker 1: little bit more sympathy for meteorologists. Right right as opposed
Speaker 1: to my friend who in college wrote an essay explaining
Speaker 1: what level of hell meteorologists should inhabit based upon Dante's Inferno,
Speaker 1: which was kind of funny, but also I'm sure meteorologists
Speaker 1: find it less. So so let's start off with just
Speaker 1: talking about the history of predicting weather, and really you
Speaker 1: have to go all the way back to early human civilization, because,
Speaker 1: as it turns out, one of the most important factors
Speaker 1: that play a part in this is the fact that
Speaker 1: we humans are pretty good at recognizing patterns. Right, So
Speaker 1: when something happens over and over, we take note of it,
Speaker 1: and we start to look at the other things that
Speaker 1: are happening over and over, and then we start to
Speaker 1: draw some hypotheses. For example, we might think that one
Speaker 1: thing could cause the next thing, or we might think
Speaker 1: one thing simply indicates the next thing is going to happen.
Speaker 1: Here's a simple example. Let's say that you are a
Speaker 1: shepherd and you notice that the flock of sheep act
Speaker 1: in a certain odd way every time it's about to rain.
Speaker 1: You might either come to the conclusion that the sheep
Speaker 1: are able to sense the rain before it actually happens,
Speaker 1: and therefore that as an indicator that is going to rain,
Speaker 1: or you might come to the conclusion that, in fact,
Speaker 1: the sheep are causing it to rain. That's probably not true.
Speaker 1: There are two ways to take that. Yeah. Yeah, But eventually,
Speaker 1: through these observations you start to eliminate possibilities and you
Speaker 1: start to draw some conclusions. Now, in early human civilizations,
Speaker 1: we're talking about very broad conclusions, things like you notice
Speaker 1: that in general, the weather gets cooler as the year
Speaker 1: goes on. You might not even have a year at
Speaker 1: this point. You may just think, as time passes, the
Speaker 1: weather gets cooler until it gets really cold, and after
Speaker 1: it's really cold for a while, it starts to get
Speaker 1: warm again, and then it gets really warm, and then
Speaker 1: it gets hot, and then the whole cycle starts over.
Speaker 1: And you may also notice that the stars the way
Speaker 1: the stars are, you can tell that they are. It's
Speaker 1: a slightly different view as this time goes on, and
Speaker 1: you start to associate, oh, when the stars get into
Speaker 1: this slow you know, this kind of configuration, It means
Speaker 1: we're getting toward the time when we should really harvest food,
Speaker 1: because we're about to go into the winter months and
Speaker 1: otherwise we're going to lose everything we've been growing, or
Speaker 1: when it's this time we should start planting food because
Speaker 1: it's the best time for us to get a big yield.
Speaker 1: Later on climate, Yeah, and you start to figure out
Speaker 1: you build out a calendar based on this, and that
Speaker 1: calendar would be fairly rough, you know, wouldn't necessarily be
Speaker 1: reflective of an actual full year, but it would be
Speaker 1: more like an indicator of what you should be expecting
Speaker 1: in the next coming time. Right, So that's your basic
Speaker 1: like big picture stuff, using things like the way animals
Speaker 1: react or certain smells that you might detect before a rainstorm.
Speaker 1: That would be sort of the more acute weather type
Speaker 1: stuff as opposed to the seasonal type stuff. And you
Speaker 1: start to draw those conclusions too, and together you start
Speaker 1: building out general rules that tell you if this one
Speaker 1: thing is happening, then here's what you should expect. This
Speaker 1: sort of pattern recognition. And in fact, today some of
Speaker 1: our data still relies on that principle. It's just that
Speaker 1: we have way more information now at a much higher
Speaker 1: precision than ancient humans did. And speaking of that, I
Speaker 1: read that there are certain Aboriginal tribes that have been
Speaker 1: observing their weather patterns for over eighteen thousand generations, so
Speaker 1: that kind of gives you a sense of how far
Speaker 1: back this goes. Yeah, and and of course, you know,
Speaker 1: if you're talking about a very specific region, like a
Speaker 1: very relatively small geographic area, you could have a pretty
Speaker 1: accurate idea of what to expect based upon those sorts
Speaker 1: of observations. They might not be presented in the super cool,
Speaker 1: high tech way that modern meteorology tends to present it,
Speaker 1: but that doesn't make it any less valid necessarily. It
Speaker 1: may be a little more rough around the edges. But
Speaker 1: if you can still tell me that, hey, in three
Speaker 1: days we're going to get some rain, and three days
Speaker 1: later it rains, and you do that reliably, that's pretty impressive. Right.
Speaker 1: So if you want to start looking at people who
Speaker 1: were really thinking about whether in kind of almost a
Speaker 1: scientific sense, and one of the first people you would
Speaker 1: have to look at his Aristotle, big brain Aristotle. He
Speaker 1: was quite the thinker. He wrote about whether in Meteorologica,
Speaker 1: and he came up with a bunch of hypotheses, some
Speaker 1: column theories, I would say hypotheses, because none of these,
Speaker 1: not all of these proved true. They came up with
Speaker 1: some hypotheses about how stuff like rain and hail, and
Speaker 1: wind and clouds and thunder and lightning and hurricanes. What
Speaker 1: made them happen, how did they behave what were the
Speaker 1: rules that governed them? And some of his ideas were
Speaker 1: mostly right and some of his ideas were way off.
Speaker 1: But the problem was without ways to measure the various
Speaker 1: metrics associated with weather, it was kind of impossible to
Speaker 1: say one way or the other. So for about two
Speaker 1: thousand years, everyone kind of just went with it because
Speaker 1: you didn't have any way of proving or disproving any
Speaker 1: of the individual ideas. But you need a basis, Yeah,
Speaker 1: you know, at least it was something. It was at
Speaker 1: least something to work from. It was just it was
Speaker 1: just a question of time. When would people develop tools
Speaker 1: that would allow them to put these ideas to the
Speaker 1: test and either see which ones are mostly right but
Speaker 1: maybe need some tweaking, or in which ones you can
Speaker 1: just completely throw out the window, Which brings us up
Speaker 1: to the Renaissance, one of my favorite time periods. As
Speaker 1: it turns out, spend a lot of time there. Our
Speaker 1: listeners can't see. But right now Jonathan has a handlebar mustache,
Speaker 1: a giant handlebar mustache, because the character I play in
Speaker 1: the Georgia Renaissance Festival has such a mustache, and I
Speaker 1: will be performing as that character the day after we
Speaker 1: record this episode. It's opening weekend for the Georgia Renaissance Festival.
Speaker 1: Would you say that someone might have a handlebar mustache
Speaker 1: in the fifteenth century, around the time of German philosopher
Speaker 1: Nicholas of Cusa, It's quite possible. I mean, there's no
Speaker 1: reason they could not have one. It's not like there
Speaker 1: were social taboos about such things. Yeah. So this philosopher,
Speaker 1: Nicholas of Cusa, designed a device to measure the amount
Speaker 1: of moisture in the air, and we call these hygrometers.
Speaker 1: These are it's really kind of a way of measuring humidity,
Speaker 1: which here in Atlanta you can pretty much just says
Speaker 1: it's humid. It's so humid. Yeah, the humidity in Atlanta
Speaker 1: is brutal, to the point where I have friends who
Speaker 1: come in from Texas, where the temperatures in Texas can
Speaker 1: get twenty degrees hotter than it gets here in Atlanta.
Speaker 1: But because Texas has relatively low humidity through most of
Speaker 1: the state, they think the weather here is way worse, like,
Speaker 1: way more difficult to deal with, But how do you
Speaker 1: measure that? And he came up with an interesting idea.
Speaker 1: Now there's there's no indication that he ever built the
Speaker 1: device he came up with, but he said, what you
Speaker 1: do is you take a set of balanced scales, so
Speaker 1: you know what those look like. They have a little
Speaker 1: dish on either side, and on one side you put
Speaker 1: a large amount of wool, and on the other side
Speaker 1: you put some weights. He said stones. Other people later
Speaker 1: on said discs of wax didn't really matter. It just
Speaker 1: had to be a counterweight of some sort. Now, the
Speaker 1: purpose of the wool is to soak up moisture in
Speaker 1: the atmosphere, which would make the wool get heavier. This
Speaker 1: is what Nicholas was saying. Like, the wool will get
Speaker 1: heavier as it soaks up water from the air, and
Speaker 1: you'll be able to tell that because the scales will
Speaker 1: start to shift and you'll see that the side with
Speaker 1: the wool will start to get heavier. Then if it
Speaker 1: dries out, if the weather gets dry, the wool will
Speaker 1: start to lose moisture. It will evaporate, and you'll start
Speaker 1: to see that side of the scale moving up. It'll
Speaker 1: get lighter. Now, he never built that, But another big
Speaker 1: thinker of the Renaissance did get around to it, Leonardo
Speaker 1: da Vinci. Yes, he did everything. Yeah, when he wasn't
Speaker 1: building helicopters or designing tanks, which he never built, but
Speaker 1: he did design. He designed a tank, and he designed
Speaker 1: a really weird I think, gosh, it was something like
Speaker 1: a thirty three barrel gun, didn't he I think a
Speaker 1: diving suit as well. Pretty much any any sort of
Speaker 1: thing that in the Renaissance would sound like it's science fiction.
Speaker 1: She had some sort of hand in. He probably has
Speaker 1: a primitive tablet schematic somewhere. Yeah. Yeah, he probably at
Speaker 1: one point came out to his patrons and showed a
Speaker 1: wooden slate and talked about how if you ran your
Speaker 1: fingers across it you could you could paginate through. And
Speaker 1: then he'd say, I think you're gonna love it, and
Speaker 1: maybe even did a one more thing. So that was
Speaker 1: the first kind of weather related instrument that people were
Speaker 1: really thinking about. Another would come in the seventeenth century
Speaker 1: early sixteen hundreds, usually put around sixteen oh three, when
Speaker 1: physicist Galileo Galile created a thermoscope, which is sort of
Speaker 1: a predecessor to a thermometer. And it was a pretty
Speaker 1: simple idea. So you start with a container that has
Speaker 1: a small amount of liquid in it, usually water. That's
Speaker 1: your base. And then you also have a kind of
Speaker 1: a hollow tube of glass that ends in a bulb,
Speaker 1: so like a larger bulb at one end and open
Speaker 1: on the other end. And you could do something like
Speaker 1: warm the bulb if you want too, in your hands.
Speaker 1: But then you would put the bulb. You would put
Speaker 1: the tube into the small container of water. The bulb
Speaker 1: would be suspended above it. Usually the hollow straw like
Speaker 1: tube would be long enough, you know, several inches long.
Speaker 1: You could then observe that as the temperature of the
Speaker 1: bulb changed, the level of water in the tube would
Speaker 1: either go up or go down. And this is because
Speaker 1: the air inside the tube is either expanding or contracting,
Speaker 1: depending upon whether it's heating up or cooling down. And
Speaker 1: this wasn't a thermometer, but it was. It was interesting,
Speaker 1: and it was once again a start. Yeah. Later on
Speaker 1: someone looked at Galileo's little invention and said, what if
Speaker 1: we put like markings on the tube so you could
Speaker 1: say how many steps up or down the tube it went.
Speaker 1: Then we could even give indications of how much warmer
Speaker 1: or cooler. You could say it's four steps warmer or
Speaker 1: four steps cooler. That became the basis of the thermometer.
Speaker 1: So and that didn't take long. It was within about
Speaker 1: fifty years that you had the first working thermometers. Following
Speaker 1: this kind of proof of concept thermoscopy, there was also
Speaker 1: there is the Galilean thermometer. Are you familiar with these?
Speaker 1: I am not. You've probably seen one. They are the
Speaker 1: cylindrical glass They're usually very decorative for for like home
Speaker 1: office desk ers, and but these glass tubes, they are cylindrical.
Speaker 1: Typically inside they have these these little glass blown glass
Speaker 1: balls that contain their own liquid. Often it's a liquid
Speaker 1: that has dye in it, so they're blue or green
Speaker 1: or red or whatever. And each one has a little
Speaker 1: weight attached to it that has a temperature. And what
Speaker 1: happens is the balls represent different densities of water, and
Speaker 1: the temperature of the glass tube will change the density
Speaker 1: of the water inside the glass tube. And then you'll
Speaker 1: see whichever ball is at the bottommost of the tube
Speaker 1: the glass tube, as that represents the general temperature, and
Speaker 1: they tend to be between like you know, like about
Speaker 1: five degrees aparts, he might have sixty five degrees seventy
Speaker 1: seventy five degrees eighty that kind of thing. So whicheveryone's
Speaker 1: at the lowest point. That's the temperature of the water,
Speaker 1: thus the temperature of the area surrounding it. I tend
Speaker 1: to be used, like I said, as decorations for desks
Speaker 1: and stuff. Galileo actually did not invent that, but some
Speaker 1: of his students did. It was several of his students,
Speaker 1: so that's why it's called a Galilean Thermometer's neat. Yeah. Yeah,
Speaker 1: it's a very pretty way of seeing, generally speaking, what
Speaker 1: temperature the tube is and therefore probably what temperature the
Speaker 1: surrounding area is. Keeping in mind that water changes temperature
Speaker 1: more slowly than something like a room would, so it
Speaker 1: wouldn't be reflected immediately, but it's still kind of interesting.
Speaker 1: We'll be back with more about weather technology after this
Speaker 1: quick break. Then we have the This is a very
Speaker 1: important tool in predicting the weather. So barometer is all
Speaker 1: about predicting, or not predicting, but measuring atmospheric pressure. So
Speaker 1: first thing, just in case you weren't aware, the atmosphere
Speaker 1: exerts pressure on us. It pushes down. Gravity is technically
Speaker 1: pulling down on the atmosphere. So the lower you are
Speaker 1: to the surface of the air, like the closer the
Speaker 1: lower down and elevation you are, the more pressure you
Speaker 1: feel from atmosphere. This is why as you climb a
Speaker 1: mountain or you get on a plane, you experience lower
Speaker 1: amounts of air pressure. It's also why you have to
Speaker 1: pressurize aircraft that fly it pretty high altitudes, otherwise you
Speaker 1: would suffer some pretty rough effects. And on the Earth's
Speaker 1: surface the force of gravity. Due to the force of gravity,
Speaker 1: the pressure is about fourteen point seven pounds per square inch. Yeah,
Speaker 1: that's a sea level. Yeah, that's what we call an
Speaker 1: atmosphere of pressure. Right one atmosphere pressure, you look at
Speaker 1: it at sea level. Specifically, you're looking at it at
Speaker 1: sea level at fifty nine degrees fahrenheit, which is fifteen
Speaker 1: degrees celsius. You have to be very specific because temperature
Speaker 1: will change pressures as you warm up air. Typically this
Speaker 1: is just a general rule of thumb. When something warms up,
Speaker 1: that means molecules are moving. That's the energy of motion. Ultimately,
Speaker 1: you're making these molecules move faster and that's kind of
Speaker 1: what heat looks like. So as molecules of air move
Speaker 1: around more, they spread out more, it becomes less dense.
Speaker 1: So that would change the atmospheric pressure as well. That's
Speaker 1: why you have to take temperature into account. When you
Speaker 1: talk about one atmosphere of pressure. That's very specific. It's
Speaker 1: at sea level at that temperature, that's one atmosphere. So
Speaker 1: that's that's kind of interesting anyway. The first person to
Speaker 1: actually create a barometer was a guy by the name
Speaker 1: of Evangelista Torricelli, and his first invention people just called
Speaker 1: Toricelli's tube, which doesn't seem very dignified. No, it needs
Speaker 1: a special name. Yeah, but Tori Chelli's tube, it wasn't
Speaker 1: quite the barometer yet. What he was doing was he
Speaker 1: was actually experimenting with the concept of vacuums, like creating
Speaker 1: a vacuum within a tube or some other container. He
Speaker 1: was just it was one of those things where we
Speaker 1: didn't fully understand what that was, how it worked, and
Speaker 1: so he did this experiment. He was actually friends with Galileo,
Speaker 1: and Galileo said, hey, Evangelista, I got an idea for you.
Speaker 1: Why don't you take one of those tubes you've been
Speaker 1: working with, and fill it with mercury and use that
Speaker 1: in your vacuum experiments. Will be a lot easier to
Speaker 1: see than some other liquid. And Tori Chelli says, all right,
Speaker 1: I'll give it a shot. So he took a four
Speaker 1: foot long glass tube and he filled the glass tube
Speaker 1: with mercury so it was closed on one end, open
Speaker 1: on the other, and then he inverted the tube into
Speaker 1: a dish, and the dish had a little bit of
Speaker 1: mercury at the bottom of it. And it showed that
Speaker 1: this the fact that the top of the tube, you know,
Speaker 1: like the mercury went all the way up this four
Speaker 1: foot tube. The liquid didn't just come rushing out and
Speaker 1: spill everywhere, right, because the vacuum is what held it
Speaker 1: in place. And he says, look, see, I was so smart.
Speaker 1: This shows that there's something working here. We're gonna really
Speaker 1: explore this. But then he noticed something else that was
Speaker 1: really interesting. He noticed that despite the fact that the
Speaker 1: tube could stay upright and the liquid would stay in
Speaker 1: there from day to day, there were variations and how
Speaker 1: high the mercury would be in the tube. And it
Speaker 1: wasn't just sinking down. It's not like it was leaking
Speaker 1: over the course of a week. So like you come
Speaker 1: back and it's a couple inches lower, and then the
Speaker 1: next day it's a couple inches lower. It wasn't like that.
Speaker 1: Some days it was actually higher. And he started thinking, well,
Speaker 1: what the heck would cause the mercury to go up
Speaker 1: or down this tube? The atmosphere that's it. The atmospheric
Speaker 1: pressure pressing down on the liquid in the dish. That's
Speaker 1: what determined whether the well, that's what to the height
Speaker 1: of the mercury inside the tube. So on days with
Speaker 1: higher atmospheric pressure, it pushes down on that exposed liquid
Speaker 1: within the dish and it forces that liquid to go
Speaker 1: up the tube, and so the height of the liquid
Speaker 1: inside the tube goes up. On days where atmospheric pressure
Speaker 1: is lower, some of that liquid comes down and starts
Speaker 1: filling up the dish until it reaches that kind of equilibrium.
Speaker 1: And then he's so he said, hey, this shows that
Speaker 1: the atmosphere itself exerts pressure. And not only that, but
Speaker 1: the pressure is not consistent day to day. It can change.
Speaker 1: And in sixteen forty four Torchelli built the first mercury barometer.
Speaker 1: So now he was building something specifically to measure this thing,
Speaker 1: because before he was really demonstrating the concept of vacuums.
Speaker 1: So now we've got the barometer, we've got the thermometer,
Speaker 1: we've got the hygrometer, essential things. Yeah, these are the
Speaker 1: basics for taking measurements about weather. And at that point
Speaker 1: it was really the start of gathering enough information so
Speaker 1: that meteorology, the science of meteorology, could actually exist, right
Speaker 1: because now we could not just observe patterns, we could
Speaker 1: actually quantify what was happening. And by quantifying it, we
Speaker 1: could get to this level of precision where we could
Speaker 1: start to draw more specific conclusions as to what would
Speaker 1: or would not happen based upon current conditions. So, all
Speaker 1: that being said, we still have some issues predicting weather.
Speaker 1: So why is that? Well, like I said before, it's complicated.
Speaker 1: So here's the thing. Our atmosphere is fluid. It's a gas,
Speaker 1: but it behaves via fluid dynamics. Dylan, have you ever
Speaker 1: studied fluid dynamics, I don't believe. So I studied them
Speaker 1: in physics and they are rutally difficult to comprehend because
Speaker 1: it can get so there's so many factors that can
Speaker 1: affect a fluid, so and the Earth has a whole
Speaker 1: bunch of them happening at once. Right. First of all,
Speaker 1: there's this big ball of plasma that's about eight and
Speaker 1: a half light minutes away from us. It's called the Sun. Yeah,
Speaker 1: you know, on nice days you might even get a
Speaker 1: glimpse of it. So the Sun provides obviously a ton
Speaker 1: of energy to the Earth and so we So the
Speaker 1: Earth absorbs a lot of solar radiation and that can
Speaker 1: affect fluid dynamics because you've got a lot of heat
Speaker 1: coming into a system. On top of that, you've got
Speaker 1: the Earth. Earth's not standing still, the Earth is rotating.
Speaker 1: That rotational force creates other fluidic effects in the atmosphere.
Speaker 1: We'll talk about those specifically when we get to high
Speaker 1: and low pressure systems. You've got gravity, which is pulling
Speaker 1: down on the fluid, so that's another force that's in play.
Speaker 1: You've got differences in surface temperature on the Earth, so
Speaker 1: you've got areas where it's very cold versus areas that
Speaker 1: are very hot. That in turn affects the atmosphere and
Speaker 1: can change things around. You have air currents a big
Speaker 1: deal there. That's also partially due to the rotation of
Speaker 1: the Earth. You've got mountain ranges which can act as
Speaker 1: like a windbreaker for certain things that changes the way
Speaker 1: weather patterns happen. Lots of things that are all in play,
Speaker 1: and some of these are localized, and some can concern
Speaker 1: large portions like air movement. Oh yeah, yeah, some of
Speaker 1: them are. Some of the effects of these can be
Speaker 1: felt hundreds of miles from where the thing happened, right,
Speaker 1: which makes it even harder because as a lady person,
Speaker 1: you sit there and think, all right, well, you know,
Speaker 1: because I can't see any clouds on the horizon, I
Speaker 1: think tonight's going to be all right, And then you
Speaker 1: could have a very fast moving system coming in due
Speaker 1: to something that happens well out of sight. It ends
Speaker 1: up creating a lot of things that could be counterintuitive,
Speaker 1: depending upon what you have at your disposal. Like, of course,
Speaker 1: the more information you have, the better conclusions you can
Speaker 1: draw in general, assuming that you also know what you're
Speaker 1: talking about. So let's talk about some of these things.
Speaker 1: These different major components that shape weather, like atmospheric pressure.
Speaker 1: So we just talked about that with barometers, But what
Speaker 1: does that mean? So what is happening? Well, I talked
Speaker 1: about how you have warm air that has air moving
Speaker 1: around a lot. That means it ends up spreading out,
Speaker 1: it becomes less dense than cold air. You probably have
Speaker 1: heard the phrase that warm air rises in cold air sinks,
Speaker 1: not entirely accurate as to what's going on. What's really
Speaker 1: happening is cold air is more dense than warm air,
Speaker 1: so cold air comes to take up the space that
Speaker 1: warm air had, which forces warm to go up. So
Speaker 1: it's not so simple as warm air rises, cold air sinks.
Speaker 1: It's more like, you know, if you've got these big
Speaker 1: heavy weights at the top, then they're going to come.
Speaker 1: They want quote unquote want, there's no desire, but they
Speaker 1: have a tendency to want to move downward, forcing the
Speaker 1: lighter stuff to go upward. That's pretty much what's happening here.
Speaker 1: So when you're talking about our atmosphere, you have to
Speaker 1: keep in mind it's three dimensional. It's not on a
Speaker 1: flat plane. That's easy to forget when we look at
Speaker 1: weather reports, because we're looking typically at a flat map,
Speaker 1: right that has a bunch of stuff like it's got
Speaker 1: little flags all over it and little lines around it,
Speaker 1: and h's and l's, and you're wondering what you know,
Speaker 1: maybe there's some clouds in there too, and but typically
Speaker 1: you're looking at a two dimensional representation. But really you
Speaker 1: have to remember that weather is a three dimensional phenomenon,
Speaker 1: so that makes it a little more complicated. Also, you
Speaker 1: got to remember the water cycles. So cold air can't
Speaker 1: hold onto moisture the way warm air can. All right,
Speaker 1: when you have warm air as close to the surface.
Speaker 1: Let's say you've got some nice, warm, moist air close
Speaker 1: to the surface of the planet, and cold air is
Speaker 1: sinking down forcing the warm air up. As the warm
Speaker 1: air rises, it's going to start to cool and as
Speaker 1: it cools, it can no longer hold onto the moisture
Speaker 1: that it had, which means the moisture starts to condense,
Speaker 1: water vapor begins to condense. This is how you get
Speaker 1: clouds and ultimately how you get stuff like precipitation. So
Speaker 1: understanding that's important. So now let's imagine way up in
Speaker 1: the atmosphere, at the top level of where our weather happens,
Speaker 1: we have these massive air currents now in cases where
Speaker 1: air currents are converging together, so you've got two air
Speaker 1: currents that are meeting up. They start to force air
Speaker 1: out of the way. Now air can't go any further
Speaker 1: up to go down, it has to go down. That's
Speaker 1: the only place to go. So that air coming down
Speaker 1: increases air pressure at that location. You have air moving
Speaker 1: down towards the surface of the Earth pushing down, your
Speaker 1: air pressure goes up. So an area of high pressure.
Speaker 1: You know what kind of weather you typically see in
Speaker 1: an area of high pressure? Clear, dry weather, Yes, exactly.
Speaker 1: So when you have high pressure system, it's typically pushing
Speaker 1: the moisture out of the way. It's it's it tends
Speaker 1: and we have to use phrases like tens or words
Speaker 1: like tens because it's not every case is equal. But
Speaker 1: it tends to be cooler, it tends to be sunny,
Speaker 1: it tends to have less wind than low pressure systems.
Speaker 1: So this high pressure system creates pleasant weather. Low pressure
Speaker 1: systems are different. Oh and also if you were to
Speaker 1: view this from the sky, like you're above this high
Speaker 1: pressure system, and if you could see air, first of all,
Speaker 1: that would be a nightmare. But if you could, you
Speaker 1: would see that the air is not just coming down
Speaker 1: like a column. It's not like it's not like you
Speaker 1: turn on a spigot of water and water just falls
Speaker 1: straight down. It's actually turning as the air is sinking right,
Speaker 1: as this high pressure system forces air downward, and it
Speaker 1: actually moves in a clockwise direction, which is funny because
Speaker 1: I was looking at Dylan a second ago and making
Speaker 1: a twisting motion, but I was doing counterclockwise. But no,
Speaker 1: it moves in a clockwise direction. This is, by the way,
Speaker 1: due to the rotational force of the Earth in part.
Speaker 1: So you've got this rotating clockwise system that's pushing air downward.
Speaker 1: That's your high pressure. We got a little bit more
Speaker 1: about WeatherTech to talk about before we get to that.
Speaker 1: Let's take another quick break. So that's your nice weather,
Speaker 1: low pressure. I think you can probably take a wild
Speaker 1: guess it's gonna mean crummy weather. Yeah, this is where
Speaker 1: you're getting clouds and rain, and typically you're talking about
Speaker 1: air being pulled upward. So why is air getting pulled upward? Well,
Speaker 1: remember I was talking about those those currents up in
Speaker 1: the upper atmosphere where they were converging together and forcing
Speaker 1: air downward. If the currents are moving apart from each other,
Speaker 1: if they're diverging, they create sort of a vacuum effect
Speaker 1: over that region, and that starts to pull air upward,
Speaker 1: creating an area of low pressure. Warm air from the
Speaker 1: surface gets pulled upward, it starts to cool down and
Speaker 1: the water vapor condenses. That's where you start getting those
Speaker 1: overcast days, the cloudiness, the rain. And on top of that,
Speaker 1: you're creating since it's a low pressure system, you're creating
Speaker 1: the opportunity for some pretty hefty winds to move in. Right,
Speaker 1: Because air is always going to move from an area
Speaker 1: of high pressure to an area of low pressure. That's
Speaker 1: just pure fluid dynamics. It makes a lot of sense
Speaker 1: if you've got like imagine that you have two water
Speaker 1: balloons connected to each other, all right, and they are
Speaker 1: in equilibrium, so they're equally full, not totally full, but
Speaker 1: equally full. If you're to squeeze one of those, creating
Speaker 1: an area of high pressure, it forces the water to
Speaker 1: go to the area of relatively lower pressure. Right, You're
Speaker 1: forcing water into that second water balloon. Same thing is
Speaker 1: true with low pressure systems. You've got a low pressure area,
Speaker 1: that means any area around it has higher pressure, air
Speaker 1: is going to want to move into the area of
Speaker 1: lower pressure. That's where you get winds coming in and
Speaker 1: it can get pretty breezy. So this one, if you
Speaker 1: were to look overhead and view the air, it would
Speaker 1: be rotating in a counterclockwise or whiter shins if you
Speaker 1: are Shakespearean direction, and the air would be coming into
Speaker 1: the low pressure system as opposed to coming out like
Speaker 1: in high pressure. It would all be moving outward in
Speaker 1: that clockwise direction, with low pressure inward in a counterclockwise direction. Now,
Speaker 1: the reason why I even bring this up is because
Speaker 1: it's important to understand how high at pressure and low
Speaker 1: pressure affect weather. So things like the wind speed, the
Speaker 1: potential for precipitation or lack of precipitation, all of those
Speaker 1: would play a part. And it's important for you to
Speaker 1: know what the pressure is of that region in order
Speaker 1: for you to make any sort of forecast. So the
Speaker 1: barometers would be the tools you would use to get
Speaker 1: those those measurements. Now, the old style barometers, the mercury ones,
Speaker 1: use fluid to indicate changes in pressure, sort of like
Speaker 1: what we were talking about with Evangelista's barometer, simply just
Speaker 1: looking to see where the level is. So area of
Speaker 1: high pressure pushes the liquid further up, you would say
Speaker 1: that pressure is rising and weather it's probably going to
Speaker 1: be pretty nice. In fact, if you ever have seen
Speaker 1: one of those old school barometers, it probably has like
Speaker 1: sunny like a little drawing of sunshine toward the top
Speaker 1: of it where the level goes up. If the if
Speaker 1: the glass is falling, if the mercury is going down
Speaker 1: the tube, then that would suggest low pressure, which suggests cloudy,
Speaker 1: nasty weather. But we also have other types of barometers.
Speaker 1: In fact, not a lot of people use the mercury
Speaker 1: ones anymore. Don't know. If you know this, Dylan, mercury
Speaker 1: is not the best thing to use. It's a little toxic. Yeah,
Speaker 1: it'll drive you crazy, you'll go mad as a hatter,
Speaker 1: but yeah. They they're also aneroid barometers, which were invented
Speaker 1: in the nineteenth century eighteen hundreds. In other words, these
Speaker 1: have a tiny little metal box and the sides are
Speaker 1: all made out of a flexible metal, and changes in
Speaker 1: pressure either push the sides of the box inward or
Speaker 1: allow the sides of the box to flex outward. That
Speaker 1: in turn is connect to tiny little levers which are
Speaker 1: connected to a needle. And then you look at your device.
Speaker 1: It can look like a little stop watch actually, and
Speaker 1: you see where the needle is and that tells you
Speaker 1: where the atmospheric pressure is at right, or you could
Speaker 1: use digital barometers, which have little pressure sensitive transducers that
Speaker 1: essentially do the same thing. They're just doing it with
Speaker 1: a transducer as opposed to an actual physical metal box.
Speaker 1: And how do we talk about these measurements, Well, it
Speaker 1: depends upon what system you're looking at. But typically weather men,
Speaker 1: meteorologists I should say weather people. I suppose that sounds
Speaker 1: like a good term. Yeah, yeah, weather people inclusive term. Yeah,
Speaker 1: a meteorologist is probably more accurate, but they use They
Speaker 1: tend to use millibars to describe atmospheric pressure, but in
Speaker 1: the US. Here in the US, we sometimes refer to
Speaker 1: inches of mercury, because darn it, we like that system.
Speaker 1: The standard scientific unit is the pascal or PA, and
Speaker 1: then there is, of course the one atmospheric pressure type approach.
Speaker 1: That's not terribly useful if you're talking about tiny changes
Speaker 1: in atmospheric pressure, like yeah, it's a point zero zero
Speaker 1: zero six atmosphere change doesn't help you very much. To me.
Speaker 1: It's kind of like measuring temperatures and celsius. It works
Speaker 1: great if you're boiling water, but if you're doing anything else,
Speaker 1: Celsius to me is just it's too brute force an
Speaker 1: approach to describe boil water. So that's perfect, right, that's
Speaker 1: really whenever I go by Dylan's desk, it's just a
Speaker 1: pot of boiling water and some photos on a screen
Speaker 1: and that's about it. So then we have temperature and
Speaker 1: moisture that those are the other two really big components.
Speaker 1: So a large body of air that has a similar
Speaker 1: temperature and moisture throughout that body of air is called
Speaker 1: an air mass. So when two air masses are near
Speaker 1: one another, they are separated by a thing called a front. Right.
Speaker 1: So you've heard of cold fronts and warm fronts obviously, right,
Speaker 1: So we'll focus on the United States. We have four
Speaker 1: major types of air masses that affect our weather here
Speaker 1: in the United States. This is not the way it
Speaker 1: is everywhere. These are the four that in general affect
Speaker 1: our weather. So you've got continental polar air masses cold
Speaker 1: and dry yep. Continental tropical air masses hot and dry, yes,
Speaker 1: which by the way, only happened in the summer and
Speaker 1: come up from Central America. That makes sense. Yeah, Then
Speaker 1: you have maritime polar cool and moist yeah. And boy,
Speaker 1: I'm so sorry for you people out there who hate
Speaker 1: the word moist, and then maritime tropical, warm and moist.
Speaker 1: There it is again. Yeah, so your content in minal
Speaker 1: polar air masses, those tend to come from our friends
Speaker 1: to the North Canada. They ship us their poutine, they're
Speaker 1: Tim Horton's coffee, and their continental polar air masses. Don't
Speaker 1: bring up Tim Hortons. I'm still bummed that there's not
Speaker 1: one here. I'm actually still look Canada. I poke a
Speaker 1: lot of fun, but I fully admit Tim Hortons is
Speaker 1: a phenomenal chain, a national treasure. I would welcome it
Speaker 1: with open arms to come here to Atlanta. Just throwing
Speaker 1: it out there. Your continental tropical, like I said, comes
Speaker 1: up through Central America and typically only affects our weather
Speaker 1: in the summer. Maritime polar that tends to come from
Speaker 1: the far northeast. So we're talking like in the New
Speaker 1: England that area maritime tropical pretty much everywhere else. And
Speaker 1: by tropical when we say hot or warm and moist,
Speaker 1: we don't necessarily mean like it feels like you're in
Speaker 1: the Caribbean. It just means not cold. Right, So the
Speaker 1: fronts tell us what sort of air is moving into
Speaker 1: an area, so a warm front. First of all, they
Speaker 1: tend to move pretty slowly. Warm fronts are not known
Speaker 1: for moving through an area quickly, and they bring lots
Speaker 1: of rain because warm fronts are pushing out cold air.
Speaker 1: So imagine you've got a massive cold air in an area.
Speaker 1: A warm front is coming in that warm air when
Speaker 1: it encounters the cold air that's already in that region,
Speaker 1: it's the warm air's inclination is to kind of go
Speaker 1: up the cold air like a ramp because again, the
Speaker 1: cold air is more dense, right, so the warm air
Speaker 1: can't just push it out of the way. The warm
Speaker 1: aare is less dense than the cold air, but it
Speaker 1: can start to go up on top of it, which
Speaker 1: means the warm are starts to cool down exactly, and
Speaker 1: that's why we get rain at the edge of a
Speaker 1: warm front. So they move pretty slowly because warm air
Speaker 1: just doesn't push cold air out very efficiently, and we
Speaker 1: get a lot of precipitation. Cold fronts where cold air
Speaker 1: replaces warm air, move faster and tend to have intense
Speaker 1: but short thunderstorms and other precipitation. As the front moves
Speaker 1: in and the weather tends to clear up pretty shortly thereafter.
Speaker 1: The reason for this is, imagine you've got a massive
Speaker 1: cold air moving in, you have warm air in the region.
Speaker 1: The cold air is going to almost act like a
Speaker 1: shovel scooping up that warm air, pushing it up into
Speaker 1: the upper levels of the atmosphere, of the lower level
Speaker 1: of the atmosphere, but the upper side of it, which
Speaker 1: cools that air down very quickly. Because of that quick cooling,
Speaker 1: you get things like bigger rainstorms thunderstorms, but they tend
Speaker 1: to happen very quickly, and then once the front has
Speaker 1: moved through, things are okay again. Spend a summer in
Speaker 1: Atlanta and you will see this phenomenon repeatedly. Right like
Speaker 1: you there was. There are times where if it's a
Speaker 1: particularly humid month, you might be able to set your
Speaker 1: watch by when the thunderstorm is going to come through.
Speaker 1: Any extreme extreme versions of it as well, not not
Speaker 1: not disaster level, but you'll see quick intense thunderstorms with
Speaker 1: hail and heavy rains and they will be gone in
Speaker 1: an hour or two yep, and then it just becomes
Speaker 1: a steam bath for the city. That's Atlanta most of
Speaker 1: the time. Yeah, but it's particularly bad about an hour
Speaker 1: after a thunderstorm. It's probably the most miserable Atlanta feels, right,
Speaker 1: because it's just it's like walking into a steam room. Yes,
Speaker 1: So again, the reason for that fast violent weather is
Speaker 1: just the speed at which that warm air is being
Speaker 1: pushed up and cooled down so that it can no
Speaker 1: longer hold on to all this moisture that was once
Speaker 1: part of it, and it has to go somewhere, so
Speaker 1: it lands on us. So that's kind of interesting. They're
Speaker 1: also stationary fronts. Stationary fronts are when two fronts just
Speaker 1: kind of collide and that's it. They're just there. It's
Speaker 1: gonna stick around for a while. You'll have a lot
Speaker 1: of rain. Typically sounds like the traffic jam of fronts. Yeah.
Speaker 1: And then there's occluded fronts, and that's when a warm
Speaker 1: front gets caught between two cooler air masses. So the
Speaker 1: warm front gets pushed up and we get a lot
Speaker 1: of intense thunderstorms with occluded fronts. Two. Hope you enjoyed
Speaker 1: that classic episode of tech stuff from twenty sixteen, Weather
Speaker 1: Tech Part One. Obviously next week we will have Weather
Speaker 1: Tech Part two as our classic episode, so make sure
Speaker 1: you come back and listen to that. If you have
Speaker 1: suggestions for future topics for tech Stuff, please reach out
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