Chapter 4 Flashcards

1
Q

How many knots does a full sock indicate?

A

15 knots

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2
Q

When is a Gust reported?

A

A gust is reported when there is at least 10 kn variation between peaks and lulls within the last 10 minutes

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3
Q

What does the letter V stand for in a metar?

A

Variable of the wind direction

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4
Q

Can you assume that there is no clouds above 15,000 feet if it says CLR IS?

A

No, there could be a cloud layer above it

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5
Q

What happens if the temperature and dew point are close together?

A

Less visibility

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6
Q

Low-pressure winds go in what direction?

A

Counterclockwise

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7
Q

Winds are always ________ to isobars ?

A

Parallel

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8
Q

Velocity = ?

A

Wind speed

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9
Q

What instrument do you use to measure wind?

A

Anemometer

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10
Q

What is the definition of a Lull?

A

Between the gust and your steady

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11
Q

What three forces effect wind or air motion?

A

Pressure gradient
Coriolis force
Friction force

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12
Q

Where will you find the boundary layer?

A

2,000 AGL

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13
Q

At what place do you find most of the friction or frequent turbulence?

A

The boundary layer

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14
Q

Where will you find a deeper boundary level?

A

higher wind speeds

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15
Q

A seabreeze comes from what direction?

A

Wind coming from the sea

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16
Q

What direction does the wind come from during a land breeze?

A

Wind comes from the land

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17
Q

At what time will you see a land breeze?

A

Night

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18
Q

At what time will you see a seabreeze

A

Day

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19
Q

When is there a frontal passage?

A

A frontal passage occurs during a change in pressure.

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20
Q

When pressure decreases and then increases what does this represent?

A

A frontal passage

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21
Q

“VV” stands for ?

A

Vertical visibility

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22
Q

Is vertical visibility considered a ceiling?

A

Yes

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23
Q

In the southern hemisphere wind rotates in what direction?

A

90° clockwise

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24
Q

In the northern hemisphere what rotates in what direction?

A

90° counterclockwise

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25
Q

What direction does a cyclone flow?

A

Counterclockwise to the right

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26
Q

what direction does an anti-cyclone flow?

A

Clockwise to the left

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27
Q

What force makes the wind want to go outward 90° to the right in the northern hemisphere and 90° left in the Southern Hemisphere?

A

Coriolis effect

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28
Q

If you are observing frontal activity what type of chart are you looking at?

A

A surface chart

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29
Q

Why is the wind skewed in surface charts?

A

Because of friction

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30
Q

When two air masses come together energy transfers creating what?

A

Weather

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31
Q

What does Coriolis effect need to work?

A

Wind

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32
Q

If the wind speed is zero, what is Coriolis speed at?

A

Zero

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33
Q

Friction is caused by high-pressure wanting to go ______ and low pressure wanting to go ________.

A

Outward and inward

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34
Q

What type of performance do you get with windshear?

A

An increase in performance

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35
Q

What type of changes do you see in wind sheer?

A

Instantaneous

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36
Q

On approach if you have a tailwind what kind of performance will you have?

A

A decrease in performance

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37
Q

If you have a headwind on approach what kind of performance will you have?

A

An increase in performance

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38
Q

Where is the lull in this metar :

33010G24K

A

10G

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39
Q

At what degree does variable wind have to be at to be present on a metar?

A

Greater than or equal to 60 degrees

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40
Q

What are the two causes of wind?

A

Pressure gradient and wind variation

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41
Q

What are the two types of wind?

A

Horizontal and vertical

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42
Q

Are cold fronts gradual or steep?

A

Steep

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43
Q

What is it called when air is being sucked up due to low-pressure

A

Convergence

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44
Q

What is it called when air is being sucked down due to high pressure

A

Divergence

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45
Q

What is it called when warm air moves upward over the cold air?

A

Frontal lifting

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46
Q

Gravity wave motions are typical in what state of air neutral, unstable or stable?

A

Stable

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47
Q

What is dry adiabatic process?

A

Cooling by expansion and warming by compressing

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48
Q

What is the temperature lapse rate for dry adiabatic process?

A

3° per thousand feet

49
Q

Is sounding reality or theory?

A

Reality

50
Q

What is Term sounding ?

A

A measurement meteorological conditions between the ground and some higher level of atmosphere

51
Q

What is the result of temperature inversion?

A

When warmer air goes up

52
Q

If LR>DALR what state is the air in stable or unstable ?

A

Unstable ,absolute

53
Q

What state is the air in for a cumulus cloud ?

A

Unstable

54
Q

What state is the air in a stratus cloud?

A

Stable air

55
Q

If you are in a field and there is a low pressure system and the wind is hitting your back what direction is the low-pressure?

A

The low-pressure is to the left

56
Q

Wind direction provided by weather observers will be oriented to_______ North

A

True

57
Q

When direction provided by air traffic controllers will be oriented to ______north

A

Magnetic

58
Q

The average speed of the wind is referred to as

A

Sustained speed

59
Q

What kind of wind speed must occur to be reported as a gust________

A

At least A-10 not variation between peaks and Lulls

60
Q

What change of wind speed must occur to be reported as a squall_________

A

Sudden increase of at least 60 kn to a sustained speed of 22 kn or more

61
Q

What does VRB mean relative to wind direction?

A

Variable

62
Q

Interpret this wind information-what is the wind direction 020V090?

A

020 variable 090

63
Q

Interpret this wind information-what is the wind speed 15G27KT

A

Wind 15 kn gusting 27 kn

64
Q

What three things make the wind “blow”?

A

Coriolis effect, Friction force, pressure gradient force

65
Q

A pressure gradient is_____

A

Difference in pressure between two points

66
Q

At what point on the planet is Coriolis force Least significant ?

A

The equator

67
Q

At what point on the planet is Coriolis force most significant?

A

The poles

68
Q

Must air move for Coriolis forced to take effect?

A

Yes

69
Q

What Coriolis force affect a strong win more than a light wind ?

A

Yes

70
Q

Geostrophic balance refers to the balance of what two forces?

A

Pressure gradient force and Coriolis force

71
Q

What is Buys-Ballot’s law ?

A

With the wind at your back, below is always on your left ( in the northern hemisphere)

72
Q

In the northern hemisphere, air moves_______, around the center of low pressure,_________ around the Center of high-pressure

A

Counterclockwise and clockwise

73
Q

Why doesn’t Geostrophic balance occur in small-scale circulations?

A

Pressure gradient force is much greater than Coriolis force

74
Q

On a 500 my constant pressure chart

A. What does the direction of the line out of the circle mean

A

Wind direction

75
Q

On a 500 mb Constant pressure chart what does one wind Barb equal

A

10 knots

76
Q

On a 500 mb constant pressure chart

C. What does 1028 mean?

A

Pressure is 1028 millibars

77
Q

On a 500 mb Constant pressure chart

D. Relative to the circle, where would you look for temperature data

A

Top left side of the data block

78
Q

On a 500 MB Constant pressure chart

E. What kind of temperature would that be

A

Centigrade

79
Q

On a 500 MB Constant pressure chart

F. Relative to the circle, where would you look for pressure Data

A

To the right side of the data block

80
Q

On a 500 MB Constant pressure chart

G. What kind of pressure would that be

A

Millibars of pressure

81
Q

When the friction over the earths surface equates to__________ Aircraft drag

A

Form or surface

82
Q

At what altitude does wind begin to change from parallels to our isobars?

A

2000 feet AGL

83
Q

In the northern hemisphere, compared to wind altitude, wind at surface shifts which Way, (left or right)?

A

Left

84
Q

Which wind is usually stronger- surface wind or wind aloft?

A

Winds aloft

85
Q

Centripetal acceleration refers to what force?

A

Centrifugal force

86
Q

Cyclostrophic balance is the balance of what two forces

A

Pressure gradient force and centrifugal force

87
Q

What balance does a tornado or present?

A

Cyclostrophic balance

88
Q

The two major lateral motions of the air are _______ and _______

A

Convergence and divergence

89
Q

The three major forces that lift air (discounting Gust) are:

A

Orographic lifting, convention (heating from the surface) , frontal lifting

90
Q

The lifting force that occurs because of displacement is

A

Frontal lifting

91
Q

When Wind blows along the surface and becomes turbulent, that kind of turbulence is called

A

Mechanical turbulence

92
Q

A mountain wave is an example of _______wind motion

A

Gravity wave

93
Q

Stability primarily refers to what condition of an air mass

A

Constant temperature

94
Q

Under what circumstance with someone describe the air as stable

A

No vertical movement

95
Q

Air buoyancy refers to what air movement

A

Vertical

96
Q

Archimedes principle is helpful in understanding air movement because

A

Heavier air displaces lighter air

97
Q

What is the gas law

A

Pressure divided by density (temp) = ratio

98
Q

How many adiabatic lapse rates are there-what are they called?

A

A. standard adiabatic lapse rate = 2°C per thousand feet
B. dry adiabatic lapse rate = 3° per thousand feet
C. Wet adiabatic lapse rate = 1° per thousand feet

99
Q

As altitude increases, pressures changes how?

A

Decreases

100
Q

During temperature changes, Expansion does what to____ Air and compression does what to______air

A

Cools and heats

101
Q

Adiabatic cooling will always accompany______ Motion and adiabatic heating Will always accompany_______motion

A

Upward and downward

102
Q

Atmospheric sounding is the process of measuring what?

A

Measuring the atmosphere

103
Q

Unsaturated Air will flow upslope at a rate of ___per thousand feet

A

104
Q

The tropospheric(ISA) lapse rate(LR) is ____Per thousand feet

A

105
Q

The DALR is ____Per thousand feet

A

106
Q

The following formula represents what kind of atmospheric stability?

LR > DALR

A

Unstable

107
Q

The following formula represent what kind of atmospheric stability?

LR

A

Stable

108
Q

The following formula represent what kind of atmospheric stability?

LR = DALR

A

Neutral

109
Q

What is the condition where warm air is above cold air?

A

Temperature inversion

110
Q

In the lower stratosphere, what is the ISA lapse rate?

A

111
Q

What formula describes “superadiabatic” instability or an unstable air mass?

A

LR >DALR

112
Q

What kind of air mass will have smoother air?

A

Stable

113
Q

What kind of air mass will have bumpy air ?

A

Unstable

114
Q

Which kind of clouds will be likely to occur and stable air?

A

Stratiform

115
Q

Which kind of clouds will be likely to occur in unstable air?

A

Cumulus

116
Q

Which conditions will be most likely to create low altitude temperature inversions?

A

Clear cool nights with Calm light winds (stable air)

117
Q

How does heating from below affect air stability?

A

Decreases stability

118
Q

Why are high pressure areas more stable than low-pressure areas?

A

High-pressure air sinks and become stable while low-pressure air rises and becomes unstable

119
Q

If your reading a meter and it states that rain ended at what time did the metal come out ?

A

It was prior to when the metar came out