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Flashcards in PPL - meteorology Deck (70):
1

What is relative humidity?

Percentage of how much moisture is in the air

100% is saturation point

2

What is the dew point?

Temperature that the air needs to cool to to become 100% saturated

3

What is the layer of atmosphere that general aviators most commonly fly in?

tropopause

4

Where is the height of the tropopause the greatest?

the equator

5

What is the standard lapse rate?

1.98°C per 1000 ft

6

What happens to the lapse rate during an inversion?

It turns negative

7

What is the dry adiabatic lapse rate and the wet rate usually?

3°C per 1000 ft for dry, and 1.5°C per 1000 ft for wet

8

What is the lapse rate for a stable atmosphere?

A shallow or negative lapse rate

9

What is the international standard atmosphere and values?

It is the set of atmospheric conditions in which the world follows as the standard. The values are:

Temperature at sea level: 15°C

Environmental lapse rate: 2°C/1000’

Pressure at sea level: 29.92” Hg

10

Can air hold more water if the temperature is hot, or cold?

hot

11

Define convection

vertical movement of air

12

Define advection

Horizontal movement of air

13

Define sublimation

when a solid changes directly to a gas

14

Define deposition

When gas changes directly to a solid

15

Define isobars

Lines of differing pressure

16

Define isotachs

Lines of wind velocity

17

In the N. Hemisphere, which way does the coriolis force deflect the air?

to the right

18

What altitude and below, does the friction force affect wind?

below 3,000’ AGL

19

In N. Hemisphere, the air revolves around a high pressure counterclockwise, or clockwise?

clockwise

20

Low pressures are know for what type of weather?

Precipitation and ascending air

21

With increasing altitude does wind tend to veer, or back?

veer

22

Relatively speaking, if the isobars are very far away, will the wind velocity be fast or slow?

slow

23

If one stands with their back to the wind in the northern hemisphere, where is the high pressure?

in front and to the right

24

What is a rapid increase in wind speed lasting for 60 seconds or longer before returning to normal speed?

A squall

25

What is the term for when the wind direction is decreasing?

Backing

26

What is the wind direction if you are heading directly into th e wind, and your heading is 276?

96

27

What is the term for when a cloud forms as the result of air moving over a colder surface?

advection

28

If a cloud has nimbo in the name, what does it mean?

It will produce precipitation

29

Mist visibility is 5/8 nm or greater while FOG vis. Is ______ than 5/8 nm

less

30

The lowest broken or overcast layer of cloud is called?

ceiling

31

If the temperature is 15°C, and the dew point is 5°C and the rest follows standard atmospheric conditions, what is the ceiling?

4000'

32

Air being warmed on the side of a mountain rises. These winds are called?

Anabatic Winds

33

The opposite of anabatic winds are?

Katabatic winds, which is when the air is cooled on the side of a mountain descendsn

34

During a sunny day, what winds are being produced on the coast of an ocean, and where are they heading in relative to the ocean and land.

A sea breeze, that heads towards land

35

What precipitation is the windward side of a mountain seeing and what is the leeward side seeing during a Chinook?

Windward side receives precip,

leeward side is dry

36

What clouds form when stable air containing moisture is blown towards a mountain, and on the leeward side becomes compressed than bounces back up in an oscillating motion?

Cap clouds, lenticular clouds, and rotors

37

What dangerous type of draft is produced as a result of mountain waves?

Downdrafts

38

When, where, and how for radiation fog

When:
Nighttime before dawn

Where:
On the surface

How:
With less than 5 kts of wind, air glides over the ground and becomes cooled until it condenses

39

Where, when and how for Advection fog

When:
Anytime

Where:
From warm surface to cold

How:
When warm air is blown over a cool surface which absorbs warmth and the air reaches its dew point

40

When, where, how for Frontal fog

When:
anytime

Where:
At a front, near the surface

How:
The warm air is above the cold and condenses, the precipitation is cooled further and evaporates in the cold air and re condensates, if this is close to the surface fog occurs

41

When, where, and how for Arctic Sea Smoke?

When:
Anytime

Where:
Over the sea

How:
The warm water evaporates than saturates the cold air above raising the dew point to meet the air temperature

42

When, where, how for upslope fog?

When:
Anytime

Where:
On mountain sides

How:
When moist air is forced to rise up the side of a mountain and when it reaches cooler air, it condenses

43

List the 4 air masses most commonly found over Canada

Maritime tropical – mT

Maritime Polar – mP

Maritime Arctic – mA

Continental Arctic – cA

44

What is the boundary between two air masses called?

A front

45

For a Cold Front, what is temperature doing?

Dropping

46

For a cold front, what is the dew point doing?

Falling

47

For a cold front, what is the Pressure doing?

While the front is approaching pressures decreases, then increases after

48

For a cold front, what is the wind doing?

Veering and increasing

49

For a cold front, what are the clouds doing?

Cirrostratus clouds that change to cumulus, then maybe nimboculumus, it will leave cumulus after passage

50

For a cold front, what is the precipitation like?

Preceded by showers, than heavy precipitation, after it passes it is showery than clear. This is all depended on stability and temperature in the warm air mass

51

For a cold front, what is the visibility like?

Bad during precip, then very good after the passage

52

For a warm front, what is the temperature doing?

rising

53

For a warm front, what is the dew point doing?

rising

54

For a warm front, what is the Pressure doing?

While it’s approaching its gonna decrease, then increase after, then usually decrease again

55

For a warm front, what is the wind doing?

Veering, but less so than with a cold front

56

For a warm front, what are clouds doing?

Cirrus and cirrostratus, then slowly lowering clouds with possible precip

57

For a warm front, what is the precip doing?

Showers usually precede the warm front, then drizze and finally after full passage its clear

58

For a warm front, what is the visibility like?

bad during precip, and hazy behind the front

59

What is the weather phenomenon when a cold front catches up to a warm front and the resulting weather is a combination between warm front clouds and cold front clouds?

Occlusions

60

Describe developing, mature, and dissipating stages of a Thunderstorm

· Developing stage: cloud is made with extremely strong updrafts, raindrops begin to form, above freezing levels ice forms, the raindrops will reach a certain size where the updrafts can no longer hold them and they begin to fall.

· Mature Stage: Begins as soon as rain reaches the earth’s surface, updrafts and downdrafts throughout cloud, friction between the two drafts create lighting and turbulence, the cloud can even reach into the stratosphere, downdrafts will spill out creating a gust front.

· Dissipating stage: Entire cloud becomes a downdraft, which removes friction from updrafts, and things start to calm down.

61

List the hazards with thunderstorms

Turbulence, hail, icing, low visibility, low ceiling, lighting, precipitation static (interferes with radios), low level, wind shear, downbursts, better performance from wind shear then sudden worsening of performance

62

What should the distance be between you and thunderstorm?

10nm

63

How often are the surface analysis charts released?

4 times per day

64

How often are METARS issued

Every hour, on the hour, 24 hours a day

65

Is visibility given in NM or SM?

Statute miles

66

Is wind direction in degrees true or magenetic?

True, it’s true on paper, magnetic when spoken. This also applies to NM for spoken, SM on paper

67

How often are GFA’s released?

4 times per day

68

What is the difference with the last GFA produced?

it contains a 12 hour IFR outlook

69

What does 00000KT mean?

Light and variable

70

What does the abbreviations “CIGS” mean?

Significant weather phenomena

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