Understanding Weather: Storms (2nd Ed, 1992)

that's [Music] Wesley calling Wesley the weather Bureau of Investigation is calling Wesley are you there Wesley this is Wesley sir are you ready for another day of training yes sir you're doing well Wesley soon you'll be a real agent like all of us at the wbi not just an agent in training what is my assignment today sir [Music] arms Wesley come in please Wesley I can hardly hear you sir what's that noise Wesley I can hardly hear you I'm out in a hurricane sir and I've never seen wind and waves like this before take shelter Wesley immediately yes sir are you in some safe place now Wesley yes sir this is where the civil defense people sent me good now stay there until the storm is over and contact me then this is Wesley calling wbi headquarters hello Wesley have things calmed down yes sir they told me it's safe to come out now that was quite a storm there's a lot of damage all over we've traced your signal and know where you are I'm sending one of the bureau's trucks to pick you up I'm in the truck sir where am I being taken to the local branch of the wbi readings from weather instruments are fed into our computers here we also get information from weather satellites look at your weather watch here's how one of these satellites looks spinning in orbit High over the Earth weather satellites send us pictures of changing Cloud patterns in our atmosphere these pictures are sped up and continually repeated to allow meteorologists to examine particular areas of clouds closely Fred are you there yes sir Fred is our chief satellite monitor Fred show Wesley how the hurricane looked from space when you first saw it developing it's on the screen now sir this movement is repeating like the cloud movement I showed you before are those clouds that's right spiraling winds have blown the clouds into that pattern hurricanes start over warm ocean waters hurricane spotters like Fred look for these Cloud patterns during the months when the ocean waters here are the warmest between the months of June and November but most often in September I know that clouds form when warm moist air rises and cools but that doesn't explain why the winds spiral or why they're so strong look at your weather watch Wesley we still have a lot to learn about the process but in general what happens is this the warm air rises and the clouds form as you said because the ocean can supply a large amount of moisture to the air more and more clouds form a thunderstorm begins out in the ocean now now because of the rotation of the earth the rising air begins to spin and move the clouds into a spiral pattern winds pick up energy from the warm moist air when the winds reach 75 mph the storm is officially called a hurricane clouds form in layers around the center of the Spiral which is called the eye the storm grows in size until it may be as much as 300 to 500 M across with winds around the eye blowing at 200 M an hour or more heavy rains fall and the strong winds produce high waves the hurricane moves slowly Northwest at about 10 m an hour pushed by the steady trade winds that blow in that part of the world you saw the destruction the hurricane could cause when it hits land but once that happens it loses its source of energy which is the warm ocean that's right and the land isn't as smooth as the ocean so that also helps the hurricane lose energy the hurricane usually breaks up into storms which you're probably more familiar with you mean thunderstorms That's Right Wesley uh would you like to take a look at a thunderstorm yes sir Fred have our driver take Wesley to the weather plane at the Airfield and I'll give the pilot instructions [Music] there's a nice thunderstorm developing in the north central part of the country where a lot of thunderstorm activity occurs you should be there in a few hours thunderstorms are a lot more common than hurricanes they can form over land as well as over water Captain come in please yes sir have you cited the storm yet yes sir just coming into view uh looks like a big one what do you see out there Wesley I see looks like a big cloud that's a kind of cloud called a Thunderhead thunderstorms May develop quickly in late afternoon when the air is warmed by the ground that's been warmed by the sun look at your weather watch here's how a Thunderhead grows in speeded up action wow it looks like the cloud is bubbling up it is moist air warmed by the land is rising and building the cloud the warm air rises because it's pushed up by cooler air that flows in under it and starts winds blowing it's the same thing that happens as a hurricane develops but on a much smaller scale while a hurricane can be as much as 500 mil across a single thunderstorm isn't usually much bigger than about 10 mil across but the storm can move faster than a hurricane does around 30 m an hour so it may move through an area where you are very quickly here in the Midwest where you are they're most common in the spring and summer Captain take Wesley to an Airfield ahead of the storm yes sir Wesley you'll be able to watch the thunderstorm approach well what do you see Wesley I see that Thunderhead I saw from the plane it's a lot bigger than I thought and it's just a part of a row of clouds that form the thunderstorm at least I know what to expect I've been through through a lot of thunderstorms thunderstorms are very common why at this very moment perhaps 2,000 are in progress in different parts of the world wow hey there's what you usually expect lightning and there's the Thunder oh I better go inside the storm should just about be there by now it's here all right here comes the r rain and it's windy too it's sort of like what happened in the hurricane just not as much rain and not nearly as strong winds right uh look at your weather watch again Wesley thunderstorms can blow down trees and power lines and cause flooding and sometimes produce something that's even more destructive what's that a tornado there's a van coming around for you Wesley you're going to join two meteorologists from the wbi who study tornadoes there's a tornado watch in your area now conditions are right for the formation of a tornado while a thunderstorm may be some 10 mil across a tornado is much smaller usually not more than about a quar of a mile across tornadoes form on the Southwest rain-free edge of the thunderstorm most tornadoes occur in the spring and develop in a storm that's moving toward the Northeast tornadoes form inside a Thunderhead when the winds there begin to spin and pull air into the cloud wind speeds increase tremendously a tornado travels along a narrow path sometimes dropping down to the ground out of the thunderheads and rising up again in an unpredictable way often causing great destruction C wherever it touches down tornado whims get too strong to be measured they've been estimated to be going as much as 300 mph around the funnel the funnel gets dark as the tornado picks up dust and dirt from the ground fortunately a tornado has a very short life and affects only a small area but as you can see tornadoes can be deadly look at the destruction they cause wow that's terrible that's why people have to know where to go to be safe when there's a tornado warning in their area Hey Wesley look over here on the left wow a real tornado yes I just got the report it's moving away from you but you'd better take cover anyway we're about to do that sir [Music] what's happening to your tornado now Wesley it's touching down sir and now it's very solid looking shaped like a funnel a funnel cloud good observation Wesley now it seems to be rising up it's gone now yes it is well Wesley you've had your share of storms today uh what can you tell me about them in what way are tornadoes thunderstorms and hurricanes alike I'll give you some visual help on your weather watch well storms all seem to be caused by warm moist air that starts Rising rapidly forming clouds and supplying energy that makes strong winds blow very good and how are they different well hurricanes form over oceans they're bigger than thunderstorms and tornadoes are smaller but much more destructive than thunderstorms over small areas good observations Wesley any questions no sir just a request could you ask the scientist in the van to open the door they got in and locked me out accidentally I guess and it looks like it's going to be raining here pretty soon in fact hello in there hello I'm still out here getting wet hello hello inside hello [Music] for for