• The thicker the atmosphere, the greater the lift and the easier it is to fly in the air.-The Future of Humanity by Kaku.

  • When a ball moves through the air, it creates turbulence in its wake, small eddy currents that cause the ball to swerve slightly and slow down. (For a baseball, these eddy currents are created by the stitching on the ball, which determines its spin. On a golf ball, it is caused by the dimples on its surface. For soccer balls, it is due to the juncture between the plates on its surface.)-The Future of Humanity by Kaku.

  • Spinning reduces the eddy currents on the ball’s surface, so it can more accurately slice through the air.-The Future of Humanity by Kaku.

  • If a baseball is thrown so that it has minimal spin (as in a knuckleball), turbulence is maximized and the ball’s path becomes erratic.-The Future of Humanity by Kaku.

  • If the Sun rise red and fiery – Wind and Rain Clouds like Rocks and Towers – Great Showers Clouds Small and round, like a Dapple-grey, with a North-Wind – Fair Weather for 2 or 3 Days Mists. If they rise in low Ground and soon vanish – Fair Weather.-The Weather Experiment by Moore.

  • The atmosphere is almost entirely made of carbon dioxide, and the atmospheric pressure is only 1 percent that of the Earth.-The Future of Humanity by Kaku.

  • Meteorology: ‘the study of things on high’.-The Weather Experiment by Moore.

  • Why, the cattle, the birds, the fish, and the reptiles, and in fact everything gave indications of coming storms, and, with the assistance of meteorological observations, scientific men should be able to give very precise notice of atmospheric changes.-The Weather Experiment by Moore.

  • Another decade would pass before the jet stream – the great artery of the atmosphere – was discovered. It was the end of the century before a Norwegian professor, Vilhelm Bjerknes, and others finally established forecasting on a sound statistical footing.-The Weather Experiment by Moore.

  • Today cyclones and anticyclones are understood as complementary opposing forces that help to transfer air around a global circulatory system. While cyclones suck air inwards and blow it out of the top, anticyclones push air outwards and down towards the ground, where it can once again be recycled by cyclones in an endless toing and froing, passing the air back and forth.-The Weather Experiment by Moore.

  • The clouds weaken as their energy source disappears. At sunset the sky is clear once again.-The Weather Experiment by Moore.

  • For twilight to properly end and night begin, the sun must be 19° beneath the horizon.-The Weather Experiment by Moore.

  • Although it is not immediately obvious, the laws of physics dictate that warm damp air like this will always rise upwards towards cooler, drier altitudes in the atmosphere. This is because atmospheric air – which is mostly formed of nitrogen and oxygen atoms – becomes lighter when water vapour molecules are mixed with it. As water vapour (H2O) is chiefly comprised of hydrogen, the lightest of all elements, it means that the damper a parcel of air, the lighter it will be and the faster it will rise. This is a fundamental principle of atmospheric science. Another is that warm air is less dense than cold air and will also rise. Anyone can observe this in their own home, opening the bathroom door after a shower and feeling the warm air escape upwards while cold air rushes in below.-The Weather Experiment by Moore.

  • On days like today strong thermals can form. From the meadow warm damp air travels upwards at surprising speeds of up to two metres a second. Invisible to us, the thermal is located by a lone hawk, who opens his wings and, without effort, soars upwards. The thermal rises over the meadow towards cooler air. The temperature drops at around 3.0°C per 1,000 feet, what is known as the dry adiabatic lapse rate. Soon the air temperature reaches a crucial juncture: the dew point. When it does water vapour begins to condense.-The Weather Experiment by Moore.

  • The process is taking place in a microscopic world. Specks of condensed water settle on minute condensation nuclei that are often no more than one ten-thousandth of a millimetre across: tiny flecks of salt, dust particles, compounds of ammonium nitrate. All have the potential to become the core of a cloud droplet. It can take billions of collisions for water vapour molecules to stick to a condensation nucleus; often they bounce off. But little by little the particles accumulate. Soon a droplet, a hundredth of a millimetre in diameter, has formed. More join. As much as 100 million of these droplets cram into a cubic metre of air. It is the beginning of a cumulus cloud. On a fine day like this, with a steady breeze, the thermals generate a production line of cumuli. They form at a fixed altitude, their flat bases tracing a dew- point line across the sky.-The Weather Experiment by Moore.

  • The cloud has a short life ahead of it. Perhaps five minutes, perhaps half an hour. The droplets of water are heavy enough to fall – the average cumulus cloud is one kilometre cubed in size and, if gathered together, would weigh more than 500 tonnes, as much as 100 African elephants – but they are kept in a state of delicate stasis by wind resistance and updraughts of rising air. Instead the cloud glides horizontally through the atmosphere on the breeze, throwing shadows over the landscape below.-The Weather Experiment by Moore.

  • Religious dogma had stifled meteorology for centuries. The weather was a potent symbol of divine vengeance and mercy, and central to the Creation story: the antediluvian paradise of Eden, the Flood, the covenant of the first rainbow. Storms were the ultimate example of God’s might. As Psalm 29 asserted, God did not just direct the weather, he was the weather. The voice of the Lord is upon the waters: the God of glory thundereth: the Lord is upon many waters. The voice of the Lord is powerful; the voice of the Lord is full of majesty. The voice of the Lord breaketh the cedars; yea, the Lord breaketh the cedars of Lebanon.-The Weather Experiment by Moore.

  • The atmosphere is divided into four unequal layers: troposphere, stratosphere, mesosphere and ionosphere (now often called the thermosphere). The troposphere is the part that’s dear to us. It alone contains enough warmth and oxygen to allow us to function, though even it swiftly becomes uncongenial to life as you climb up through it. From ground level to its highest point, the troposphere (or “turning sphere”) is about 16 kilometres thick at the equator and no more than 10 or 11 kilometres high in the temperate latitudes where most of us live. Eighty per cent of the atmosphere’s mass, virtually all the water and thus virtually all the weather are contained within this thin and wispy layer.-A Short History by Bryson.

  • Beyond the troposphere is the stratosphere. When you see the top of a storm cloud flattening out into the classic anvil shape, you are looking at the boundary between the troposphere and the stratosphere. This invisible ceiling is known as the tropopause and was discovered in 1902 by a Frenchman in a balloon, Léon-Philippe Teisserenc de Bort. Pause in this sense doesn’t mean to stop momentarily but to cease altogether; it’s from the same Greek root as menopause.-A Short History by Bryson.

  • After you have left the troposphere the temperature soon warms up again, to about 4 degrees Celsius, thanks to the absorptive effects of ozone (something else de Bort discovered on his daring 1902 ascent). It then plunges to as low as minus 90 degrees Celsius in the mesosphere before skyrocketing to 1,500 degrees Celsius or more in the aptly named but very erratic thermosphere, where temperatures can vary by over 500 degrees from day to night—though it must be said that “temperature” at such a height becomes a somewhat notional concept. Temperature is really just a measure of the activity of molecules. At sea level, air molecules are so thick that one molecule can move only the tiniest distance—about eight-millionths of a centimeter, to be precise—before banging into another. Because trillions of molecules are constantly colliding, a lot of heat gets exchanged. But at the height of the thermosphere, at 80 kilometres or more, the air is so thin that any two molecules will be miles apart and hardly ever come into contact. So although each molecule is very warm, there are few interactions between them and thus little heat transference.-A Short History by Bryson.

  • As the afternoon wears on the cloud base begins to thicken. Strong convective currents propel parcels of moist air higher into the atmosphere where they start to sublime into ice crystals. The cumulus clouds with their cauliflower tops have coalesced and a cumulonimbus is growing fast. In the right conditions a cumulonimbus capillatus can tower for many miles over the landscape, its anvil top scraping along the boundary between the troposphere and the stratosphere. As the tallest structure on earth, the cumulonimbus gives meaning to the expression ‘to be on cloud nine’, – the nine being the number assigned to the cloud by the International Cloud Atlas in 1896.-The Weather Experiment by Moore.

  • In supercooled air inside the cumulonimbus, ice crystals like those found in cirrus clouds extend outwards in an enormous canopy. On days like this raindrops can be sucked inside the cloud by powerful updraughts from below and sent see-sawing up and down, creating concentric rings of ice that tumble to earth as hail. But today the ice crystals fall straight. They melt as they descend into the warmer air below. It is the start of a rain shower.-The Weather Experiment by Moore.

  • As the raindrops fall they pass through a shaft of sunlight, refracting it, and on the ground half a mile away someone standing with their back to the sun looks up at an angle of 42°. They see a rainbow.-The Weather Experiment by Moore. 

  • A second bow is almost always visible over the primary rainbow, at an angle of 51.-The Weather Experiment by Moore.

  • The Coriolis effect explains why anything moving through the air in a straight line laterally to the Earth’s spin will, given enough distance, seem to curve to the right in the northern hemisphere and to the left in the southern as the Earth revolves beneath it. The standard way to envision this is to imagine yourself at the centre of a large carousel and tossing a ball to someone positioned on the edge. By the time the ball gets to the perimeter, the target person has moved on and the ball passes behind him. From his perspective, it looks as if it has curved away from him. That is the Coriolis effect and it is what gives weather systems their curl and sends hurricanes spinning off like tops. The Coriolis effect is also why naval guns firing artillery shells have to adjust to left or right; a shell fired 15 miles would otherwise deviate by about 100 yards and plop harmlessly into the sea.-A Short History by Bryson.

Warm Front

  • Warm Air Mass arrives and rises above a colder air mass.

  • Signs: Low Pressure, High Humidity, Low Ceiling.

  • Result: Fairly Calm Winds (max of 20 mph) at fronts leading edge, steady rain for days.

Cold Front

  • Fast Moving, unstable cold air pushes under warm air ahead, forcing it up quickly and cooling it.

  • Signs: High P, High cloud ceiling, good vis.

  • Result: fair weather and heat can change quickly, strong winds (generally from the North or West, and severe but brief thunderstorms or snow squalls).

Occluded Front

  • Three converging air masses- a fast moving cold front overtakes a warm front, lifting (occluding) the warm air mass. The incoming cold front then collides with the departing cold air mass.

  • Signs: Wind direction change, falling then rising P.

  • Results: Storms possible, light to heavy rain followed by dry weather after front exits.

  • Weather Patterns: Air cools by 5.5 degrees/1000’ (dry air), add humidity and rate slows to 3.2 degrees/1000’.

Geographic Areas

  • MOUNTAINS: Winds follow upslope during the day as the air heats up, then downslope in the cool evening. The earlier you submit, the less windy and cloudy it will be.

  • VALLEYS: Cold Air Sinks

  • OCEANS/SEAS/LAKES: During the day, breezes blow inland as air flows from the colder water to the warmer land. At night, gusts travel from the cool land towards the warmer water.

  • Coastal Wind on a cloudy day signals an approaching front and likely storm

  • GLACIERS & SNOW FIELDS: Create downslope breezes that travel about a ⅓ of a mile below them.

  • DESERTS: Thermals- columns of rising air that occurs over hot spots on land or water. Air rushes to fill the columns low pressure zones, spawning sandstorms w/ up to 75mph wings (more likely in afternoon).

Predictors

  • Red Sky at Night, Sailors Delight: Redness is caused by sun rays reflecting off dust particles when there's little cloud cover and stable air. US weather is typically from the West, so a red sky at dusk means a HP system. A Red Sky as the sun rises in the East means the HP system has already passed and a LP storm system may be approaching, especially if the sky is a deep , fiery red (signs of H2O vapor).

  • Birds don't fly before storms

  • Stir your coffee, it creates bubbles, if the bubbles amass in the center: HP (makes surface convex), if bubbles form a ring around the sides of the mug: LP (makes surface concave)

  • Smoke rising straight up: HP, if on a calm night the smoke disperses after hugging the ground: LP

 

  • Because heat from the Sun is unevenly distributed, differences in air pressure arise on the planet. Air can’t abide this, so it rushes around trying to equalize things everywhere. Wind is simply the air’s way of trying to keep things in balance. Air always flows from areas of high pressure to areas of low pressure and the greater the discrepancy in pressures, the faster the wind blows.-A Short History by Bryson.

  • A typical weather front may consist of 750 million tonnes of cold air pinned beneath a billion tonnes of warmer air.-A Short History by Bryson.

  • Moist, warm air from the equatorial regions rises until it hits the barrier of the tropopause and spreads out. As it travels away from the equator and cools, it sinks. When it hits bottom, some of the sinking air looks for an area of low pressure to fill and heads back for the equator, completing the circuit. At the equator the convection process is generally stable and the weather predictably fair, but in temperate zones the patterns are far more seasonal, localized and random, which results in an endless battle between systems of high-pressure and low-pressure air. Low-pressure systems are created by rising air, which conveys water molecules into the sky, forming clouds and eventually rain. Warm air can hold more moisture than cool air, which is why tropical and summer storms tend to be the heaviest. Thus low areas tend to be associated with cloud and rain, and highs generally spell sunshine and fair weather. When two such systems meet, it often becomes manifest in the clouds. For instance, stratus clouds—those unlovable, featureless sprawls that give us our overcast skies—happen when moisture-bearing updraughts lack the oomph to break through a level of more stable air above, and instead spread out, like smoke hitting a ceiling.-A Short History by Bryson.

  • Briton George Hadley, who saw that rising and falling columns of air tended to produce “cells” (known ever since as “Hadley cells”).-A Short History by Bryson.

Wind

  • Jet Stream flows from west to east with speed of up to 150mph (Prevailing Westerlies = wind for Continental USA).

  • The wind cycle starts from a very simple source: warm air rising, cool air falling. Over and over the cycle repeats, with masses of warm air replaced by cooler air, and vice versa. The more drastic the temperature difference, the stronger the wind.

  • Jet streams, usually located about 9,000–10,000 metres up, can bowl along at up to nearly 300 kilometres an hour and vastly influence weather systems over whole continents.-A Short History by Bryson.

 

Pressure/Frontal Systems

  • Cooling Air starts to sink because it gets heavy. As pressure builds within the sinking air, a high is born.

  • When the air is rising as water or land heats up, the air is less heavy and a low is created.

  • Land heats faster than water, so in coastal areas in the summer the land is usually warmer than the massive body of water next to it. During the day, the low pressure of the faster-rising air over the land is open invitation to higher-pressure, cooler air over the water. As the cool air moves towards the warmer air, we feel it as a welcome breeze coming from the sea.

  • At night, the sea breeze may blow the other way in southerly areas such as Florida. There, the ocean water is warm, and as night falls, the air above the ocean is under less pressure than the cooler air over the land. Highs always move towards lows, so the breeze blows toward the ocean.

  • A sudden change in temperature announces a front's arrival

  • Dropping pressure often means rain is coming, while a rising barometer indicates the approach or arrival of clear weather.

 

Dew Point

  • The dew point temperature is the exact moment when gas turns to liquid

 

Humidity

  • As Air warms, its relative humidity decreases, but the warmer air allows more water to evaporate into it before it becomes saturated.

  • Warmer air, with its greater capacity to hold water vapor, has a higher dew point than cooler air. If the dew point is high, humidity and temperature are also high. As air rises, it expands and cools off, eventually reaching its dew point, the temperature at which condensation occurs. At dew point, the air is completely saturated and relative humidity is 100%.

 

Fog/Dew/Frost 

  • As air cools, its relative humidity increases. If it becomes cool enough, fog, dew, or frost may form.

  • Fog usually doesn’t last long. As the sun warms the air, the water in it moves back to vapor state, and the fog burns off. 

  • Fog is more common near the coast, especially the Pacific. Moisture-laden air cools as wind sweeps it across the cooler ocean, forming fog over the water. When the breeze blows it inland, you get the famous San-Francisco fog.

 

Heat 

  • Heat Transfer

    • Convection: Transfer of heat through a fluid by molecular motion. q= hT.

      • q: local heat flux density (W/m2)

      • h: heat transfer coefficient (WK/m2)

      • T: temperature difference (K)

    • Conduction: Transfer of heat by direct contact. High KE molecules is passed to lower KE molecules. q= -kT

      • q: local heat flux density (W/m2)

      • k: materials conductivity (W/mK)

      • T: temperature gradient (K/m)

    • Radiation: Transfer of heat through EM waves. q= q= esT^4

      • q: power radiated from an object (W/m2)

      • s: Stefan-Boltzmann Constant (Wm2K4)

      • e: emissivity of the surface of a material.

  

Clouds

  • Water droplets and ice crystals in the sky can be big enough to send the sun's entire spectrum scattering. The result is white light- which we see as clouds.  

  • Nimbus is added to dark clouds, Higher clouds get ALTO attached.

  • A fluffy summer cumulus several hundred metres to a side may contain no more than 100–150 litres of water—“about enough to fill a bathtub.”-A Short History by Bryson.

 

Water Cycle

  • The Water Cycle: When air cools as it rises over a mountain, clouds form as the water vapor condenses, causing the side of the mountain facing the prevailing winds to receive more than its share of rain. By the time the air crests the mountain, very little moisture is left in it. The leeward side of the mountain is in the "rain shadow," it's much drier and warmer.

 

Moon

  • Ring around the moon, rain is coming soon, larger the ring, nearer the rain

 

Sun

  • A glorious sunset, full of pink, orange, red, and purple clouds, foretells good weather the next day.

Thunderstorms

  • For reasons not entirely understood, the lighter particles tend to become positively charged and to be wafted by air currents to the top of the cloud. The heavier particles linger at the base, accumulating negative charges. These negatively charged particles have a powerful urge to rush to the positively charged Earth and good luck to anything that gets in their way. A bolt of lightning travels at 435,000 kilometres an hour and can heat the air around it to a decidedly crisp 28,000 degrees Celsius, several times hotter than the surface of the sun.-A Short History by Bryson.

Hurricanes (aka Cyclones aka Typhoons)

  • The first step in that transformation is the development of a tropical storm, which happens when a group of t-storm circles until it develops into a vortex. Very few t-storms develop into tropical storms, as wind shear usually destroys the vortex, or a turbulent atmosphere, or LP in the upper troposphere, combine to prevent the circulation and buildup of winds. Tropical storms intensify into hurricanes only where the surface temperature of the ocean is around 78F or greater. This is because hot seawater evaporates readily, providing the volume of fuel- water vapor- required to power a hurricane.-The Weather Makers by Flannery.