Commercial – Chapter 7 – Aviation Weather

Question 1 of 97

1. Question

Every physical process of weather is accompanied by or is the result of

a heat exchange.
the movement of air.
a pressure differential.

Question 2 of 97

2. Question

Moisture is added to a parcel of air by

sublimation and condensation.
evaporation and condensation.
evaporation and sublimation.

Question 3 of 97

3. Question

In the Northern Hemisphere, the wind is deflected to the

right by Coriolis force.
right by surface friction.
left by Coriolis force.

Question 4 of 97

4. Question

Why does the wind have a tendency to flow parallel to the isobars above the friction level?

Coriolis force tends to counterbalance the horizontal pressure gradient.
Coriolis force acts perpendicular to a line connecting the highs and lows.
Friction of the air with the Earth deflects the air perpendicular to the pressure gradient.

Question 5 of 97

5. Question

With regard to windflow patterns shown on surface analysis charts; when the isobars are

close together, the pressure gradient force is slight and wind velocities are weaker.
not close together, the pressure gradient force is greater and wind velocities are stronger.
close together, the pressure gradient force is greater and wind velocities are stronger.

Question 6 of 97

6. Question

What causes wind?

The Earth's rotation.
Air mass modification.
Pressure differences.

Question 7 of 97

7. Question

Which is true regarding a cold front occlusion? The air ahead of the warm front

is colder than the air behind the overtaking cold front.
is warmer than the air behind the overtaking cold front.
has the same temperature as the air behind the overtaking cold front.

Question 8 of 97

8. Question

On Surface Analysis Charts, widely spaced isobars indicate a

weak pressure gradient.
strong pressure gradient.
relatively turbulent wind.

Question 9 of 97

9. Question

Which is true with respect to a high- or low-pressure system?

A high-pressure area or ridge is an area of rising air.
A low-pressure area or trough is an area of descending air.
A high-pressure area or ridge is an area of descending air.

Question 10 of 97

10. Question

Which is true regarding high- or low-pressure systems?

A high-pressure area or ridge is an area of rising air.
A low-pressure area or trough is an area of rising air.
Both high- and low-pressure areas are characterized by descending air.

Question 11 of 97

11. Question

While flying cross-country in the Northern Hemisphere, you experience a continuous left crosswind which is associated with a major wind system. This indicates that you

are flying toward an area of generally unfavorable weather conditions.
have flown from an area of unfavorable weather conditions.
cannot determine weather conditions without knowing pressure changes.

Question 12 of 97

12. Question

When flying into a low-pressure area in the Northern Hemisphere, the wind direction and velocity will be from the

left and decreasing.
left and increasing.
right and decreasing.

Question 13 of 97

13. Question

What prevents air from flowing directly from high-pressure areas to low-pressure areas?

Coriolis force.
Surface friction.
Pressure gradient force.

Question 14 of 97

14. Question

The general circulation of air associated with a high-pressure area in the Northern Hemisphere is

outward, downward, and clockwise.
outward, upward, and clockwise.
inward, downward, and clockwise.

Question 15 of 97

15. Question

The wind system associated with a low-pressure area in the Northern Hemisphere is

an anticyclone and is caused by descending cold air.
a cyclone and is caused by Coriolis force.
an anticyclone and is caused by Coriolis force.

Question 16 of 97

16. Question

During the winter months in the middle latitudes, the jet stream shifts toward the

north and speed decreases.
south and speed increases.
north and speed increases.

Question 17 of 97

17. Question

The strength and location of the jet stream is normally

weaker and farther north in the summer.
stronger and farther north in the winter.
stronger and farther north in the summer.

Question 18 of 97

18. Question

A common location of clear air turbulence is

in an upper trough on the polar side of a jet stream.
near a ridge aloft on the equatorial side of a high-pressure flow.
south of an east/west oriented high-pressure ridge in its dissipating stage.

Question 19 of 97

19. Question

The jet stream and associated clear air turbulence can sometimes be visually identified in flight by

dust or haze at flight level.
long streaks of cirrus clouds.
a constant outside air temperature.

Question 20 of 97

20. Question

A strong wind shear can be expected

in the jet stream front above a core having a speed of 60 to 90 knots.
if the 5°C isotherms are spaced between 7° to 10° of latitude.
on the low-pressure side of a jet stream core where the speed at the core is stronger than 110 knots.

Question 21 of 97

21. Question

Which type of jet stream can be expected to cause the greater turbulence?

A straight jet stream associated with a low-pressure trough.
A curving jet stream associated with a deep low-pressure trough.
A jet stream occurring during the summer at the lower latitudes.

Question 22 of 97

22. Question

Which feature is associated with the tropopause?

Constant height above the Earth.
Abrupt change in temperature lapse rate.
Absolute upper limit of cloud formation.

Question 23 of 97

23. Question

What is the standard temperature at 10,000 feet?

-5°C.
-15°C.
+5°C.

Question 24 of 97

24. Question

What are the standard temperature and pressure values for sea level?

.15°C and 29.92" Hg.
59°F and 1013.2" Hg.
15°C and 29.92 Mb.

Question 25 of 97

25. Question

What is the standard temperature at 20,000 feet?

-15°C.
-20°C.
-25°C.

Question 26 of 97

26. Question

Which is true regarding actual air temperature and dew point temperature spread? The temperature spread

decreases as the relative humidity decreases.
decreases as the relative humidity increases.
increases as the relative humidity increases.

Question 27 of 97

27. Question

What is the standard temperature at 6,500 feet?

15°C.
2°C.
38°F.

Question 28 of 97

28. Question

Which cloud types would indicate convective turbulence?

Cirrus clouds.
Nimbostratus clouds.
Towering cumulus clouds.

Question 29 of 97

29. Question

Which combination of weather-producing variables would likely result in cumuliform-type clouds, good visibility, and showery rain?

Stable, moist air and orographic lifting.
Unstable, moist air and orographic lifting.
Unstable, moist air and no lifting mechanism.

Question 30 of 97

30. Question

Which are characteristics of a cold air mass moving over a warm surface?

Cumuliform clouds, turbulence, and poor visibility.
Cumuliform clouds, turbulence, and good visibility.
Stratiform clouds, smooth air, and poor visibility.

Question 31 of 97

31. Question

What is the approximate base of the cumulus clouds if the temperature at 2,000 feet MSL is 10°C and the dew point is 1°C?

3,000 feet MSL.
4,000 feet MSL.
6,000 feet MSL.

Question 32 of 97

32. Question

What determines the structure or type of clouds which will form as a result of air being forced to ascend?

The method by which the air is lifted.
The stability of the air before lifting occurs.
The relative humidity of the air after lifting occurs.

Question 33 of 97

33. Question

The presence of standing lenticular altocumulus clouds is a good indication of

lenticular ice formation in calm air.
very strong turbulence.
heavy icing conditions.

Question 34 of 97

34. Question

Virga is best described as

streamers of precipitation trailing beneath clouds which evaporate before reaching the ground.
wall cloud torrents trailing beneath cumulonimbus clouds which dissipate before reaching the ground.
turbulent areas beneath cumulonimbus clouds.

Question 35 of 97

35. Question

Fog produced by frontal activity is a result of saturation due to

nocturnal cooling.
adiabatic cooling.
evaporation of precipitation.

Question 36 of 97

36. Question

Which in-flight hazard is most commonly associated with warm fronts?

Advection fog.
Radiation fog.
Precipitation-induced fog.

Question 37 of 97

37. Question

A situation most conducive to the formation of advection fog is

a light breeze moving colder air over a water surface.
an air mass moving inland from the coastline during the winter.
a warm, moist air mass settling over a cool surface under no-wind conditions.

Question 38 of 97

38. Question

Advection fog has drifted over a coastal airport during the day. What may tend to dissipate or lift this fog into low stratus clouds?

Nighttime cooling.
Surface radiation.
Wind 15 knots or stronger.

Question 39 of 97

39. Question

What lifts advection fog into low stratus clouds?

Nighttime cooling.
Dryness of the underlying land mass.
Surface winds of approximately 15 knots or stronger.

Question 40 of 97

40. Question

Which conditions are favorable for the formation of a surface based temperature inversion?

Clear, cool nights with calm or light wind.
Area of unstable air rapidly transferring heat from the surface.
Broad areas of cumulus clouds with smooth, level bases at the same altitude.

Question 41 of 97

41. Question

In what ways do advection fog, radiation fog, and steam fog differ in their formation or location?

Radiation fog is restricted to land areas; advection fog is most common along coastal areas; steam fog forms over a water surface.
Advection fog deepens as wind speed increases up to 20 knots; steam fog requires calm or very light wind; radiation fog forms when the ground or water cools the air by radiation.
Steam fog forms from moist air moving over a colder surface; advection fog requires cold air over a warmer surface; radiation fog is produced by radiational cooling of the ground.

Question 42 of 97

42. Question

With respect to advection fog, which statement is true?

It is slow to develop and dissipates quite rapidly.
It forms almost exclusively at night or near daybreak.
It can appear suddenly during day or night, and it is more persistent than radiation fog.

Question 43 of 97

43. Question

What are the characteristics of stable air?

Good visibility; steady precipitation; stratus clouds.
Poor visibility; steady precipitation; stratus clouds.
Poor visibility; intermittent precipitation; cumulus clouds.

Question 44 of 97

44. Question

Which would decrease the stability of an air mass?

Warming from below.
Cooling from below.
Decrease in water vapor.

Question 45 of 97

45. Question

What is a characteristic of stable air?

Stratiform clouds.
Fair weather cumulus clouds.
Temperature decreases rapidly with altitude.

Question 46 of 97

46. Question

Which would increase the stability of an air mass?

Warming from below.
Cooling from below.
Decrease in water vapor.

Question 47 of 97

47. Question

Which is a characteristic of stable air?

Cumuliform clouds.
Excellent visibility.
Restricted visibility.

Question 48 of 97

48. Question

Which is a characteristic typical of a stable air mass?

Cumuliform clouds.
Showery precipitation.
Continuous precipitation.

Question 49 of 97

49. Question

What type weather can one expect from moist, unstable air, and very warm surface temperature?

Fog and low stratus clouds.
Continuous heavy precipitation.
Strong updrafts and cumulonimbus clouds.

Question 50 of 97

50. Question

A moist, unstable air mass is characterized by

poor visibility and smooth air.
cumuliform clouds and showery precipitation.
stratiform clouds and continuous precipitation.

Question 51 of 97

51. Question

If clouds form as a result of very stable, moist air being forced to ascend a mountain slope, the clouds will be

cirrus type with no vertical development or turbulence.
cumulus type with considerable vertical development and turbulence.
stratus type with little vertical development and little or no turbulence.

Question 52 of 97

52. Question

The formation of either predominantly stratiform or predominantly cumuliform clouds is dependent upon the

source of lift.
stability of the air being lifted.
temperature of the air being lifted.

Question 53 of 97

53. Question

When an air mass is stable, which of these conditions is most likely to exist?

Numerous towering cumulus and cumulonimbus clouds.
Moderate to severe turbulence at the lower levels.
Smoke, dust, haze, etc., concentrated at the lower levels with resulting poor visibility.

Question 54 of 97

54. Question

Which is true regarding the development of convective circulation?

Cool air must sink to force the warm air upward.
Warm air is less dense and rises on its own accord.
Warmer air covers a larger surface area than the cool air; therefore, the warmer air is less dense and rises.

Question 55 of 97

55. Question

When conditionally unstable air with high-moisture content and very warm surface temperature is forecast, one can expect what type of weather?

Strong updrafts and stratonimbus clouds.
Restricted visibility near the surface over a large area.
Strong updrafts and cumulonimbus clouds.

Question 56 of 97

56. Question

Convective circulation patterns associated with sea breezes are caused by

water absorbing and radiating heat faster than the land.
land absorbing and radiating heat faster than the water.
cool and less dense air moving inland from over the water, causing it to rise.

Question 57 of 97

57. Question

From which measurement of the atmosphere can stability be determined?

Atmospheric pressure.
The ambient lapse rate.
The dry adiabatic lapse rate.

Question 58 of 97

58. Question

The difference found by subtracting the temperature of a parcel of air theoretically lifted from the surface to 500 millibars and the existing temperature at 500 millibars is called the

lifted index.
negative index.
positive index.

Question 59 of 97

59. Question

The conditions necessary for the formation of stratiform clouds are a lifting action and

unstable, dry air.
stable, moist air.
unstable, moist air.

Question 60 of 97

60. Question

What visible signs indicate extreme turbulence in thunderstorms?

Base of the clouds near the surface, heavy rain, and hail.
Low ceiling and visibility, hail, and precipitation static.
Cumulonimbus clouds, very frequent lightning, and roll clouds.

Question 61 of 97

61. Question

What feature is normally associated with the cumulus stage of a thunderstorm?

Roll cloud.
Continuous updraft.
Beginning of rain at the surface.

Question 62 of 97

62. Question

The conditions necessary for the formation of cumulonimbus clouds are a lifting action and

unstable, dry air.
stable, moist air.
unstable, moist air.

Question 63 of 97

63. Question

The most severe weather conditions, such as destructive winds, heavy hail, and tornadoes, are generally associated with

slow-moving warm fronts which slope above the tropopause.
squall lines.
fast-moving occluded fronts.

Question 64 of 97

64. Question

Of the following, which is accurate regarding turbulence associated with thunderstorms?

Outside the clouds, shear turbulence can be encountered 50 miles laterally from a severe storm.
Shear turbulence is encountered only inside cumulonimbus clouds or within a 5-mile radius of them.
Outside the cloud, shear turbulence can be encountered 20 miles laterally from a severe storm.

Question 65 of 97

65. Question

Which statement is true concerning squall lines?

They form slowly, but move rapidly.
They are associated with frontal systems only.
They offer the most intense weather hazards to aircraft.

Question 66 of 97

66. Question

Which statement is true regarding squall lines?

They are always associated with cold fronts.
They are slow in forming, but rapid in movement.
They are nonfrontal and often contain severe, steady-state thunderstorms.

Question 67 of 97

67. Question

Select the true statement pertaining to the life cycle of a thunderstorm.

Updrafts continue to develop throughout the dissipating stage of a thunderstorm.
The beginning of rain at the Earth's surface indicates the mature stage of the thunderstorm.
The beginning of rain at the Earth's surface indicates the dissipating stage of the thunderstorm.

Question 68 of 97

68. Question

Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?

The start of rain.
The appearance of an anvil top.
Growth rate of cloud is maximum.

Question 69 of 97

69. Question

During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?

Mature.
Developing.
Dissipating.

Question 70 of 97

70. Question

What minimum distance should exist between intense radar echoes before any attempt is made to fly between these thunderstorms?

20 miles.
30 miles.
40 miles.

Question 71 of 97

71. Question

Which is true regarding the use of airborne weather-avoidance radar for the recognition of certain weather conditions?

The radarscope provides no assurance of avoiding instrument weather conditions.
The avoidance of hail is assured when flying between and just clear of the most intense echoes.
The clear area between intense echoes indicates that visual sighting of storms can be maintained when flying between the echoes.

Question 72 of 97

72. Question

Which situation would most likely result in freezing precipitation? Rain falling from air which has a temperature of

32°F or less into air having a temperature of more than 32°F.
0°C or less into air having a temperature of 0°C or more.
more than 32°F into air having a temperature of 32°F or less.

Question 73 of 97

73. Question

If airborne radar is indicating an extremely intense thunderstorm echo, this thunderstorm should be avoided by a distance of at least

20 miles.
10 miles.
5 miles.

Question 74 of 97

74. Question

Hail is most likely to be associated with

cumulus clouds.
cumulonimbus clouds.
stratocumulus clouds.

Question 75 of 97

75. Question

Ice pellets encountered during flight normally are evidence that

a warm front has passed.
a warm front is about to pass.
there are thunderstorms in the area.

Question 76 of 97

76. Question

The greatest threats to an aircraft operating in the vicinity of thunderstorms are:

thunder and heavy rain.
hail and turbulence.
precipitation static and low visibility.

Question 77 of 97

77. Question

Which statement is true concerning the hazards of hail?

Hail damage in horizontal flight is minimal due to the vertical movement of hail in the clouds.
Rain at the surface is a reliable indication of no hail aloft.
Hailstones may be encountered in clear air several miles from a thunderstorm.

Question 78 of 97

78. Question

Ice pellets encountered during flight are normally evidence that

a cold front has passed.
there are thunderstorms in the area.
freezing rain exists at higher altitude.

Question 79 of 97

79. Question

What is indicated if ice pellets are encountered at 8,000 feet?

Freezing rain at higher altitude.
You are approaching an area of thunderstorms.
You will encounter hail if you continue your flight.

Question 80 of 97

80. Question

Thunderstorms identified as severe or giving an intense radar echo should be avoided by what distance?

5 miles.
At least 25 miles.
At least 20 miles.

Question 81 of 97

81. Question

On initial climbout after takeoff and with the autopilot engaged, you encounter icing conditions. In this situation you can expect

ice to accumulate on the underside of the wings due to the higher AOA.
the autopilot to hold the vertical speed, if the anti-icing boots are working.
the increased airflow under the wings to prevent the accumulation of ice.

Question 82 of 97

82. Question

A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as

light chop.
light turbulence.
moderate turbulence.

Question 83 of 97

83. Question

When turbulence causes changes in altitude and/or attitude, but aircraft control remains positive, that should be reported as

light.
severe.
moderate.

Question 84 of 97

84. Question

Turbulence that is encountered above 15,000 feet AGL not associated with cumuliform cloudiness, including thunderstorms, should be reported as

severe turbulence.
clear air turbulence.
convective turbulence.

Question 85 of 97

85. Question

The minimum vertical wind shear value critical for probable moderate or greater turbulence is

4 knots per 1,000 feet.
5 knots per 1,000 feet.
8 knots per 1,000 feet.

Question 86 of 97

86. Question

One of the most dangerous features of mountain waves is the turbulent areas in and

below rotor clouds.
above rotor clouds.
below lenticular clouds.

Question 87 of 97

87. Question

The conditions most favorable to wave formation over mountainous areas are a layer of

stable air at mountaintop altitude and a wind of at least 20 knots blowing across the ridge.
unstable air at mountaintop altitude and a wind of at least 20 knots blowing across the ridge.
moist, unstable air at mountaintop altitude and a wind of less than 5 knots blowing across the ridge.

Question 88 of 97

88. Question

When flying low over hilly terrain, ridges, or mountain ranges, the greatest potential danger from turbulent air currents will usually be encountered on the

leeward side when flying with a tailwind.
leeward side when flying into the wind.
windward side when flying into the wind.

Question 89 of 97

89. Question

Convective currents are most active on warm summer afternoons when winds are

light.
moderate.
strong.

Question 90 of 97

90. Question

During departure, under conditions of suspected low-level wind shear, a sudden decrease in headwind will cause

a loss in airspeed equal to the decrease in wind velocity.
a gain in airspeed equal to the decrease in wind velocity.
no change in airspeed, but groundspeed will decrease.

Question 91 of 97

91. Question

During an approach, the most important and most easily recognized means of being alerted to possible wind shear is monitoring the

amount of trim required to relieve control pressures.
heading changes necessary to remain on the runway centerline.
power and vertical velocity required to remain on the proper glidepath.

Question 92 of 97

92. Question

The Low Level Wind Shear Alert System (LLWAS) provides wind data and software process to detect the presence of a

rotating column of air extending from a cumulonimbus cloud.
change in wind direction and/or speed within a very short distance above the airport.
downward motion of the air associated with continuous winds blowing with an easterly component due to the rotation of the Earth.

Question 93 of 97

93. Question

What is an important characteristic of wind shear?

It is present at only lower levels and exists in a horizontal direction.
It is present at any level and exists in only a vertical direction.
It can be present at any level and can exist in both a horizontal and vertical direction.

Question 94 of 97

94. Question

Low-level wind shear may occur when

surface winds are light and variable.
there is a low-level temperature inversion with strong winds above the inversion.
surface winds are above 15 knots and there is no change in wind direction and windspeed with height.

Question 95 of 97

95. Question

Hazardous wind shear is commonly encountered

near warm or stationary frontal activity.
when the wind velocity is stronger than 35 knots.
in areas of temperature inversion and near thunderstorms.

Question 96 of 97

96. Question

If a temperature inversion is encountered immediately after takeoff or during an approach to a landing, a potential hazard exists due to

wind shear.
strong surface winds.
strong convective currents.

Question 97 of 97

97. Question

GIVEN:

Winds at 3,000 feet AGL Surface winds 30 kts Calm

While on approach for landing, under clear skies with convective turbulence a few hours after sunrise, one should

increase approach airspeed slightly above normal to avoid stalling.
keep the approach airspeed at or slightly below normal to compensate for floating.
not alter the approach airspeed, these conditions are nearly ideal.