1. Living in Our Ocean of Air Chapter 1-2 WX Elements

2. Source: http://www. geog. ucsb

3. Angle of incoming radiation and hours of sunlight affect heating.
Source:

4. Wind will flow from high to low.

5. Hot air rises generating an area of low pressure.
Air cools as it rises and falls generating an area of high pressure.

6. In the northern hemisphere, low pressure rotates in a counterclockwise direction.
In the northern hemisphere, high pressure rotates in a clockwise direction.
Source:

8. Wind Facts
Air moves horizontally from an area of high pressure to an area of low pressure.

9. Wind speed is measured with an anemometer.
Wind Facts
Wind speed is measured with an anemometer.

10. Wind Facts is cooling caused by the wind.
Local winds blow over a short distance.

11. Wind Facts
sea breeze- air over the water is cooler and denser than air over land. The flow is from higher pressure to lower pressure.

12. Wind Facts
land breeze - at night air over land is cooler and denser. Air flows from higher pressure to lower pressure.

13. Wind Facts
Global winds blow steadily from specific directions over long distances.
Why did Columbus land
In the Caribbean Islands?
Wind Graphic Display

14. Gaspard Gustave de Coriolis
Wind Facts
Gaspard Gustave de Coriolis
The Coriolis Effect, curvature of the wind, is caused by Earth’s rotation.

15. Wind Facts
Jet streams are high-speed winds about 10 km above Earth’s surface.
What’s happening right now? What does it mean for weather for the next little while?

16. Dust Storm

17. Links
GOES satellite image index
Weatherunderground.com

18. Types of Clouds
Clouds-The three general types of clouds are cumulus, stratus, and cirrus. All other types come from these three and are usually referred to as low, middle, and high.

19. Cumulus Stratus Cirrus
TYPE
Cumulus
(pile up)
Stratus
(layered)
Cirrus
(wispy)
LOW
Alt:
MIDDLE
HIGH
Clouds-The three general types of clouds are cumulus, stratus, and cirrus. All other types come from these three and are usually referred to as low, middle, and high.

20. Low Clouds Stratus Sheet - like cloud. No turbulence.
May be risen fog.
Light drizzle or snow.
Close to Earth’s surface.
Can hide danger.
Low - Beginning at the lower altitudes, between 300 and 6,500 feet.
Stratus
Low, gray, uniform, sheet-like cloud with a smooth appearance.
Indicates accurately to aviators that no turbulence is associated with the cloud.
May be fog that has developed and risen a few hundred or so feet above the Earth's surface.
If precipitation does occur, it will be a light drizzle or in the form of snow grains during the wintertime.
A simple stratus produces little precipitation because it is relatively thin. A cloud must be at least 4,000 feet thick to produce significant precipitation.
Can cause problems to aviators because it can lie close enough to the Earth's surface that it could close airports to aircraft and pilots who are not equipped and/or qualified to penetrate such cloud formations.
Can hide the fact that pilots are flying into or toward unfavorable or dangerous situations.

21. Low Clouds Stratocumulus Rolls or global masses. Bulbous protrusions.
Heavy rain and snow
Varying turbulence.
Masks higher severe cloud buildups.
Stratocumulus
Gray or blue, individual rolls or global masses with similar layering characteristics as stratus clouds.
Has bulbous protrusions on the upper side and usually is rather thick.
Heavier rains and snow can be expected from this type of cloud.
Turbulence of varying intensity can also be expected near the base of the layer.
To aviators the appearance of stratocumulus ahead is a warning that flight under the formation most likely will encounter "zero-zero" visibility and probably strong turbulence.
The stratocumulus can mask higher and more severe cloud buildups.

22. Low Clouds Cumulonimbus Vertical growth group. Top has anvil shape.
High winds, snow, hail, rain, lightning, and tornadoes.
Extreme turbulence.
Cumulonimbus
Belonging to the clouds with vertical growth group and is also known as thunderstorm clouds.
Can grow to heights that reach the tropopause. At these heights, the top of the cloud is flattened out into an anvil shape by high winds.
High winds, snow, hail, rain, lightning, and tornadoes are associated with these clouds.
Storms developed in this cloud are more likely to occur in the afternoon and early evening because of the effects of the Sun's heating.
The chief danger it offers all aircraft, particularly light aircraft, is extreme turbulence inside the cloud.

23. Low Clouds Nimbostratus Shapeless, low-level, moderate precipitation.
Fog and precipitation found beneath.
Visibility restricted.
Calm to light winds.
Nimbostratus
Dark gray, thick, shapeless, low-level clouds that produce light to moderate falling precipitation including ice particles and snow if temperatures are cold enough.
The Sun and Moon are not visible through the cloud.
Fog and precipitation are found beneath and around the cloud causing the determination of the base to be difficult.
Visibility is greatly restricted by the precipitation.
Calm to light surface winds are associated with the nimbostratus cloud.

24. Middle Clouds Altostratus Relatively thin.
Sun may be seen through veil.
Ice crystals and super-cooled water.
Light precipitation.
Poor surface visibility.
Middle - Starting at 6,500 feet and extending to 20,000 feet, the stratus and cumulus shapes are found, but at this altitude they are known as altostratus and altocumulus.
Altostratus
The simple altostratus usually is relatively thin.
It produces a gray or blue veil through with the Sun may be dimly seen.
Due to its altitude, its condensate may be ice crystals and super-cooled water.
If precipitation is produced, it will be very light.
Usually associated with poor surface visibility with smooth air and moderate surface winds.

25. Middle Clouds Altocumulus Wavy solid clouds with rounded outline.
Light intermittent rain or snow.
Commonly followed by thunderstorms.
Poor visibility and moderate surface winds.
Altocumulus
White or gray layers, rolls or patches of wavy solid clouds with a rounded outline.
Normally produces light intermittent rain or snow.
The presence of altocumulus clouds on a warm humid morning is common followed by a thunderstorm late in the day.
Turbulence is normally found in the altocumulus cloud with generally good surface visibility.

26. High Clouds Cirrus Thin feathery clouds. No precipitation.
Sign of approaching bad weather.
High - Found at 20,000 feet and higher, cirrus, cirrostratus, and cirrocumulus types of clouds appear.
Cirrus
White, thin feathery clouds found in patches or bands. They are commonly called "mares' tails."
Precipitation doesn't fall from these clouds because of the high altitude.
Usually a sign of approaching bad weather.

27. High Clouds Cirrostratus Thin, resembles a sheet or veil.
No precipitation.
Nearly transparent.
Often sign of approaching bad weather.
Cirrostratus
White; thin cloud layers that resemble a sheet or veil.
Precipitation doesn't fall from these clouds because of the high altitude.
Because of the thin surface (nearly transparent) the Sun/Moon can easily be seen through them.
Often a sign of approaching bad weather; surface winds bring overcast skies.

28. High Clouds Cirrocumulus Thin clouds.
Indicates high-level instability.
Similar to cirrostratus but they have a slightly “bumpy” appearance.
Cirrocumulus
Thin clouds in sheets; individual elements look like tufts of cotton.
Indicates high-level instability.
Similar to cirrostratus but have a slightly "bumpy” appearance.

29. Fracto and Lenticular Fracto Lenticular Broken and/or ragged.
Cumulus fractos.
Lenticular
Lens-like shape.
Tells turbulence, visibility, precipitation.
Fracto and Lenticular
Another term associated with the various cloud types is "fracto". Meaning "broken and /or ragged".
Combine fracto with stratus to describe a broken stratus layer, fracto-stratus.
There is a special type of cloud, which frequently forms as strong winds sweep up and over the tops of high mountains.
It is called a lenticular formation and its name is the result of its lens-like shape.
A lenticular can, and does, form over areas other than mountain areas.
These clouds tell what can be expected with regard to turbulence, visibility and precipitation.
Fracto and Lenticular
Another term associated with the various cloud types is “fracto”. Meaning “broken and/or ragged”.
Combine fracto with stratus to describe a broken stratus layer – fracto stratus.
There is a special type of cloud, which frequently forms as strong winds, sweeps up and over the tops of high mountains.
It is called a lenticular formation and its name is the result of its lens-like shape.
A lenticular cloud can form over areas other than mountain areas.
These clouds indicate what can be expected with regard to turbulence, visibility, and precipitation.

30. Cumulus with Vertical Growth
Fair weather cumulus
A puffy, cottonball appearance.
Develops from thermal updrafts.
Flights below can be bumpy and choppy.
Cumulus with Vertical Growth
Fair weather cumulus.
A puffy, cottonball appearance with a horizontal dark base.
It develops from thermal or updrafts of heated air containing a relatively small amount of water vapor.
Flights below fair weather cumulus can be bumpy and choppy because of updrafts beneath the clouds.

31. Cumulus with Vertical Growth
Vertical growth, or building cumulus
Produce strong rain and moderate to severe turbulence.
Very strong updrafts.
With further building and increase in intensity, it becomes a thunderstorm.
Cumulus with vertical growth, or building cumulus.
These clouds produce strong rain showers with moderate to severe turbulence and probably will develop into a thunderstorm.
Very strong updrafts are characteristic of these clouds as they build higher and larger. This type of growth continues until the cloud becomes cumulonimbus.
With further building and increase in intensity, it becomes a thunderstorm.

32. Fog Types Radiation Fog
Formed at night when land surfaces radiate much of the heat absorbed from the Sun back into space.
The cool land surface cools the air near it to below the dew point and fog is formed.
Fog Types
NOTE: Fog is actually a cloud because it is developed within the atmosphere, but is considered as a separate classification because of the conditions under which it is formed.
Radiation Fog
Formed at night when land surfaces radiate much of the heat absorbed from the Sun back into space.
The cool land surface cools the air near it to below the dew point and fog is formed.

33. Fog Types High Inversion Fog A low fog.
Formed by condensation of water vapor at or near the top of cool air, which is overlain by a warmer air layer.
High Inversion Fog
A low fog.
Formed by condensation of water vapor at or near the top of cool air, which is overlain by a warmer air layer.

34. Air Mass Type and Origination

35. Air Mass Type and Origination
Air masses are identified by letter symbols.
A polar air mass (P) is cold.
A tropical air mass (T) is hot.
A maritime air mass (m) forms over water and is humid.
A continental air mass (c) forms over land and is dry.
Air mass type and origination
Air masses are identified by letter symbols.
A polar air mass (P) is cold.
A tropical air mass (T) is hot.
A maritime air mass (m) forms over water and is humid.
A continental air mass (c) forms over land and is dry.

36. Air Mass Type and Origination
Aviators and meteorologists in the continental United States are chiefly concerned with air masses origination at two sources.
Masses that move southward from Polar Regions.
Masses that move northward from Tropical Regions.
Aviators and meteorologists in the continental United States are chiefly concerned with air masses origination at two sources.
Masses that move southward from Polar Regions.
Masses that move northward from Tropical Regions.

37. Air Mass Type and Origination
Cold air masses
Continental polar (cP)
Maritime polar (mP)
Arctic (A)
The principle warm air mass is maritime tropic (mT)
Cold air masses
Continental polar (cP)
Maritime polar (mP)
Arctic (A)

38. Temperature Classification of Air Masses
Based upon its temperature in relation to the surface over which it passes.
A cold air mass (k) is cooler than the Earth’s surface over which it is moving.
A warm air mass (w) is warmer than the Earth’s surface over which it is moving.
Temperature Classification of Air Masses
Based upon its temperature in relation to the surface over which it passes.
A cold air mass (k) is cooler than the Earth's surface over which it is moving.
A warm air mass (w) is warmer than the Earth's surface over which it is moving.

39. Temperature Classification of Air Masses
Continental polar cold (cPk) - originates in the polar zone and moves south over a warm surface.
Maritime tropical warm (mTw) - originates over the Gulf of Mexico and moves toward the north over a cold surface.
An air mass originating in the polar zone and moving toward the south over a comparatively warm surface is identified by the symbol (cPk); continental polar cold.
An air mass originating over the Gulf of Mexico and moving toward the north over a comparatively cold surface is identified by the symbol (mTw); maritime tropical warm.

40. Characteristics of Air Masses
As an air mass moves away from its source, its original characteristics are changed because of the surface it passes over. It may:
Become warmer or colder.
Absorb or lose moisture.
Be lifted up by mountains or subside into valleys.
Cold air masses move more rapidly than warm air masses.
As an air mass moves away from its source, its original characteristics are changed because of the surface it passes over.
It may become warmer or colder.
It may absorb or lose moisture.
It may be lifted up by mountains or subside into valleys.

41. Fronts
The boundaries between air masses are called frontal zones or fronts.
This boundary or front moves along the Earth’s surface as one air mass displaces another.
If a cold air mass replaces a warmer air mass, the boundary is called a cold front.
If a warm air mass replaces a cold air mass, the boundary is called a warm front.
Fronts
The boundaries between air masses of different characteristics are called frontal zones or fronts.
This boundary or front moves along the Earth's surface as one air mass displaces another.
If a cold air mass replaces a warmer air mass, the boundary is called a cold front.
If a warm air mass replaces a cold air mass, the boundary is called a warm front.

42. Cold Front

43. Fronts
Cold Fronts
As warm air is forced upward, it cools, condenses into clouds, creating thunderstorms.
If movement is rapid, with an abundance of water vapor, violent weather takes place.
Squall lines develop ahead of the front.
As warm, humid air is forced upward, it cools and water vapor condenses into clouds that create thunderstorms.
If the movement of the cold air mass is rapid and there is abundant water vapor ahead of it, very violent weather takes place.
Lines of thunderstorms (squall lines) develop ahead of the front (from 50 to 150 miles).

44. Fronts
Cold Fronts
Along the cold front there will be a low-pressure cell where the weather is at its worst.
Almost any type of clouds can be found near the cell.
Poor visibility, low ceilings and rain in summer.
Freezing rain and snow in winter.
Along the cold front there will be a low-pressure cell where weather will be at its worst.
Almost any type of cloud can be found near the cell because of highly concentrated water vapor and the temperature and dew points are very close.
In the summer aviators can expect very poor visibility, low ceilings, and a lot of rain.
In the winter it causes freezing rain and snow.

45. Warm Front

46. Fronts
Warm Fronts
Connected to a low-pressure cell, travels northeastward.
If cell did not move, the front would dissipate.
Front slips upward over cool air and forms a wedge.
Rises slowly which delays condensation.
Warm Fronts
The usual warm front is connected to a low-pressure cell, extends "eastward" from it, and travels northeastward.
If the low-pressure cell did not move, the warm front would travel counterclockwise around the cell until it dissipated.
Since warm air is less dense than cool or cold air, the leading edge of a warm front slips upward and over the cooler air, forming a wedge shape.
The warm air rises slowly and its rate of cooling (lapse rate) is slow, which results in "delayed" condensation of the water vapor.

47. Fronts Warm Fronts Front is announced by cirrus clouds.
As front approaches other clouds, skies darken.
Near the frontal boundary, clouds are low, gentle rain falls and visibility is poor.
Warm rain falling into cooler air causes fog.
The approaching warm front is announced by the appearance of cirrus clouds. The cirrus may be as much as 1,000 miles in advance of the front.
As the front approaches other types of clouds appear, and the sky grows darker. Eventually rain falls.
Very near the frontal boundary, clouds usually are low; gentle rain falls and visibility is poor.
Often the falling of warm rain into the cooler air near the surface produces fog.

48. Fronts
Warm Fronts
After front passes, there is a rise in temperatures, general clearing and change in wind direction.
In winter a warm front causes icing conditions at low altitudes.
In northern latitudes snow may also be produced.
After the front passes, there is a further rise in temperature, general clearing, and change in wind direction.
In the winter months the passage of a warm front usually causes icing conditions at very low altitudes which may extend downward to the Earth's surface.
In more northern latitudes snow may also be associated with the warm front.

49. Stationary Front

50. Fronts Stationary Front
When air masses stop, a stationary front develops.
Weather can be bad for aviation along the front.
About every form of weather can be found.
Stationary Front
When air masses stop moving, a stationary front develops.
The weather along a stationary front can be very bad for aviation.
In parts of the country where there is a large amount of moisture, just about every form of weather can be found along the stationary front.

51. Front Stationary Front
Toward the trailing edge of the any front there will be a stationary-front condition.
The trailing edge stationary fronts are a great distance from the parent cell.
As the distance become greater the front no longer exists.
Toward the trailing edge of any front there will be a stationary-front condition, because a frontal zone cannot go on forever.
These "trailing edge" stationary fronts are a great distance from the parent pressure cell that continues to move.
At some point the distance becomes so great that the identity between cold and warm air is lost, and the front in that area no longer exists.

52. Occluded Front

53. Front
Occluded Front
There is a tendency for a horizontal bend or wave to occur along the front.
After a frontal bend starts, cold air moves ahead of a warm front.
The cold section moves faster than the warm section.
Occluded Front
Under certain conditions there is a tendency for a horizontal bend or wave to occur along a front.
After the frontal bends start, cold air moves in such a way that it retreats ahead of a warm front in an adjacent section.
The cold front section moves faster that the warm front section and it overtakes the warm front. The warm air mass between the fronts is lifted above the surface by the two colder air masses.

54. Terrain Factors
The presence of mountain ranges change the characteristics of a front.
As air masses enter the United States the mountains cause them to rise.
Along many seacoasts there is a breeze from the sea by day. This moist, relatively cool air rises and heats as it passes across land.
Convectional clouds form and bring afternoon showers.
Terrain Factors
The presence of mountain ranges in the path of a weather front can change the characteristics of the front greatly. Gentle rolling hills also contribute to the manufacturing of weather.
As air masses enter the United States, the mountains cause them to rise.
As the air rises, it cools and loses practically 100 percent of its moisture on the windward (facing the wind) slope.
The leeward slopes remain dry.
Along many seacoasts, there is a breeze from the sea by day. This moist, relatively cool air rises and heats as it passes across land.
Convectional clouds form a short distance inland and may bring afternoon showers.

55. Terrain Factors
At night the land cools and the breeze blows toward the sea.
Wind blowing toward land formations and condensation will occur.
The reverse can happen if the wind forces clouds downward into warmer air.
Terrain Factors
At night the land cools more rapidly than the sea, the current is reversed, and the breeze blows from land to sea.
Wind blowing toward land formations that slope gently upward can carry moisture-laden air to the altitude where its dew point temperature is located and condensation will occur.
The reverse can happen if the wind forces clouds downward into warmer air. The clouds will again become water vapor.

56. Turbulence Thermal Turbulence
Intense surface heating causes convection currents.
More intense convection currents occur over dark-colored ground.
Less convection currents will be over light-colored ground.
Because velocity varies turbulent conditions are expected.
Turbulence
Thermal turbulence - caused by intense surface heating.
Intense surface heating will create columns of rising air called convection currents or thermals.
More intense convection currents will be present over dark-colored ground such as a black asphalt highway.
Less intense convection currents will be present over light-colored ground such as wheat fields.
Because the velocity of these currents varies according to the nature of the underlying surface, turbulent conditions should be expected.

57. Turbulence Thermal Turbulence
Presents the biggest problem for aviators during landing.
To eliminate during normal flight, climb above clouds.
Not confined to summer months.
When cumulus clouds are present, convection currents and thermal turbulence exists.
Thermal turbulence presents the biggest problem for aviators during the landing portion of the flight due to the increased tendency to either overshoot or undershoot the runway.
To eliminate thermal turbulence during normal flights, climb above any cumulus clouds present.
Thermal turbulence is not confined to only summer months.
Anytime cumulus clouds are present, convection currents exists and thermal turbulence exists.

58. Turbulence Mechanical Turbulence - Low Level
Results from strong wind gusts over rough terrain or manmade features.
Produces turbulent eddies below 500 feet.
Mechanical turbulence - caused by friction, the interaction of the air with another surface.
Low level mechanical turbulence.
Results from strong, gusty winds flowing over rough terrain or manmade features.
This flow will produce turbulent eddies making flight conditions poor in the atmospheric layer below 500 feet.

59. Turbulence Mechanical Turbulence - Mountain Wave
Caused by wind speeds of 25 knots or stronger.
Produces a large-scale wave motion.
Extends from ground level to tropopause and 300 nmi downwind.
Most intense turbulence will occur within the first two or three waves.
Mountain wave turbulence
Caused by wind speeds of 25 knots or stronger flowing perpendicular to a line of hills or mountains.
These conditions will produce a phenomenon in which a large-scale wave motion develops downwind from the mountain range.
The turbulent effects of this wave motion can extend from ground level to the tropopause and downwind as far as 300 nmi.
Normally, the most intense turbulence will occur within the first two or three waves.

60. Turbulence - Wind Shear
VIDEO OF WIND SHEAR

61. Turbulence Wind Shear - Low Level Wind Shear (LLWS)
Occurs below 10,000 feet.
Primarily caused by frontal systems, low level jet streams and thunderstorms.
Occurs rapidly.
Wind Shear - caused by a sudden change in wind direction, wind speed or both for a short distance.
Low level wind shear (LLWS).
Occurs at altitude below 10,000 feet.
Primarily caused by frontal systems, low level jetstreams, and thunderstorms.
Low level wind shear occurs quite rapidly; therefore, a pilot should anticipate turbulence and be prepared to respond when conditions are present or forecasted.