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92 Cards in this Set
- Front
- Back
Every physical process of weather is accompanied by or is the result of
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a heat exchange
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Moisture is added to a parcel of air by
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evaporation and sublimation
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In the northern Hemisphere, the wind is deflected to the
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right by coriolis force
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Why does the wind have a tendency to flow parallel to the isobars above the friction level
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Coriolis force tends to counterbalance the horizontal pressure gradient
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With regard to windflow patterns shown on surface analysis charts; when the isobars are
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close together, the pressure gradient force is greater and wind velocities are stronger
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what causes wind
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pressure differences
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which is true regarding a cold front occlusion? The air ahead of the warm front
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is warmer than the air behind the overtaking cold front
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8. which is true with respect to a high-or low-pressure system
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a high-pressure area or ridge is an area of descending air
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9. Which is true regarding high- or low-pressure systems?
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a low-pressure area or trough is an area of rising air
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10. 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
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are flying toward an area of generally unfavorable weather conditions
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11. when flying into a low-pressure area in the Northern Hemisphere, the wind direction and velocity will be from the
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left and increasing
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12. what prevents air from flowing directly from high-pressure areas to low-pressure areas?
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coriolis force
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13. the general circulation of air associated with a high-pressure area in the northern hemisphere is
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outward, downward, and clockwise
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14. the wind system associated with a low-pressure area in the northern hemisphere is
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a cyclone and is caused by coriolis force
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15. During the winter months in the middle latitudes, the jet stream shifts toward the
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south and speed increases
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16. the strength and location of the jet stream is normally
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weaker and farther north in the summer
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17. A common location of clear air turbulence is
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in an upper trough on the polar side of a jet stream
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18. the jet stream and associated clear air turbulence can sometimes be visually identified in flight by
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long streaks of cirrus clouds
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19. a strong wind shear can be expected
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on the low-pressure side of a jetstream core where the speed at the core is stronger than 110 knots
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20. which type of jetstream can be expected to cause the greater turbulence
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a curving jetstream associated with a deep low-pressure trough
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21. Which feature is associated with the tropopause
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abrupt change in temperature lapse rate
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22. what is the standard temperature at 10,000 feet?
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-5'C
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23. What are the standard temperature and pressure values for sea level?
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15'C and 29.92" Hg.
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24. What is the standard temperature at 20,000 feet?
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-25'C
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25. Which is true regarding actual air temperature and dew point temperature spread? the temperature spread
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decreases as the relative humidity increases
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26. which cloud types would indicate convective turbulence?
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towering cumulus clouds
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27. Which combination of weather-producing variables would likely result in cumuliform-type clouds, good visibility, and showery rain
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unstable, moist air and orthographic lifting
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28. Which are characteristics of a cold air mass moving over a warm surface?
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cumuliform clouds, turbulence, and good visibility
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29.What is the approximate base of the cumulus clouds if the temerature at 2,000 feet MSL is 10'C and the dew point is 1'C?
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6,000 feet MSL
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30. What determines the structure or type of clouds which will form as a result of air being forced to ascend
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the stability of the air before lifting occurs
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31. the presence of standing lenticular altocumulus clouds is a good indication of?
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very strong turbulence
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32. Virga is best described as
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streamers of precipitation trailing beneath clouds which evaporate before reaching the ground
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33. Fog produced by frontal activity is a result of saturation due to
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evaporation of precipitation
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34. Which in-flight hazard is most commonly associated with warm fronts?
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precipitation-induced fog
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35. A situation most conducive tot he formation of advection fog is
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an air mass moving inland from the coastline during the winter
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36. Advection fog has drifted over coastal airport during the day. What may tend to dissipate or lift this fog into low stratus clouds?
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wind 15 knots or stronger
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37. What lifts advection fog into low stratus clouds
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Surface winds of approximately 15 knots or stronger
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38. Which conditions are favorable for the formation of a surface based temperature inversion
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clear, cool nights with calm or light wind
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39. In what ways do advection fog, radiation fog, and steam fog differ their formation or location?
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radiation fog is restricted to land areas; advection fog is most common along coastal areas; steam fog forms over a water surface
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40. with respect to advection fog, which statement is true?
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it can appear suddenly during day or night, and it is more persistent than radiation fog
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41.what are characteristics of stable air
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poor visibility; steady precipitation; stratus clouds.
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42.which would decrease the stability of an air mass
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warming from below
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43.what is a characteristic of stable air
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stratiform clouds
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44. which would increase the stability of an air mass
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cooling from below
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45. Which is a characteristic of stable air
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restricted visibility
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46. Which is a characteristic typical of a stable air mass?
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continuous precipitation
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47. What type weather can one expect from moist, unstable air, and very warm surface temperature
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strong updrafts and cumulonimbus clouds
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48. A moist, unstable air mass is characterized by
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cumuliform clouds and showery precipitation
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49. If cloud form as a result of very stable, moist air being forced to ascend a mountain slope, the clouds will be
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stratus type with little vertical development and little or no turbulence
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50. The formation of either predominantly stratiform or predominately cumuliform clouds is dependent upon the
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stability of the air being lifted
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When an air mass is stable, which of these conditions is most likely to exist?
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Smoke, dust, haze, etc., concentrated at the lower levels with resulting poor visibility
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52. Which is true regarding the development of convective circulation
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Cool air must sink to force the warm air upward
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53. When conditionally unstable air with high-moisture content and very warm surface temperature is forecast, one can expect what type of weather?
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strong updrafts and cumulonimbus clouds
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54. Convective circulation patterns associated with sea breezes are caused by
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land absorbing and radiating heat faster than the water
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55. from which measurement of the atmosphere can stability be determined
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the ambient lapse rate
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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
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lifted index
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57. the conditions necessary for the formation of stratiform clouds are a lifting action and
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stable, moist air
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58. What visible signs indicate extreme turbulence in thunderstorms
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Cumulonimbus clouds, very frequent lightning, and roll clouds
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59. What feature is normally associated with the cumulus stage of a thunderstorm
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Continuous updraft
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60. The conditions necessary for the formation of cumulonimbus clouds are a lifting actions and
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unstable, moist air
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61. The most severe weather conditions, such as destructive winds, heavy tail, and tornadoes, are generally associated with
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squall lines
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62. Of the following, which is accurate regarding turbulence associated with thunderstorms
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outside the cloud, shear turbulence can be encountered 20 miles laterally from a severe storm
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63. Which statement is true concerning squall lines?
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they offer the most intense weather hazards to aircraft
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64. Which statement is true regarding squall lines
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they are nonfrontal and often contain severe, steady-state thunderstorms
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65. Select the true statement pertaining to the life cycle of a thunderstorm
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the beginning of rain at the Earth's surface indicates the mature stage of the thunderstorm
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66. Which is true regarding the use of airborne weather-avoidance radar for the recognition of certain weather conditions
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the radarscope provides no assurance of avoiding instrument weather conditions
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67. Which weather phenomenon signals the beginning of the mature stage of a thunderstorm
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the start of rain
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68. During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts
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dissipating
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What minimum distance should exist between intense radar echoes before any attempt is made to fly between these thunderstorms
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40 miles
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70. which situation would most likely result in freezing precipitation? rain falling from air which has a temperature of
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more than 32 'F into air having temperature of 32'F or less
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71. If airborne radar is indicating an extremely intense thunderstorm echo, this thunderstorm should be avoided by a distance of at least
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20 miles
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72. which statement is true concerning the hazards of hail
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hailstones may be encountered in clear air several miles from a thnderstorm
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73. Hail is most likely to be associated with
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cumulonimbus clouds
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74. Ice pellets encountered during flight normally are evidence that
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a warm front is about to pass
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75. Ice pellets encountered during flight are normally evidence that
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freezing rain exists at higher altitude
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76. What is indicated if ice pellets are encountered at 8,000 feet
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freezing rain at higher altitude
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77. A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as
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light turbulence
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78. When turbulence causes changes in altitude and/or attitude, but aircraft control remains positive, that should be reported as
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moderate
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Turbulence that is encountered above 15,000 feet AGL not associated with cumuliform cloudiness, including thunderstorms, should be reported as
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clear air turbulence
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80. The minimum vertical wind shear value critical for probable moderate or greater turbulence is
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6 knots per 1,000 feet
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One of the most dangerous features of mountain waves is the turbulent areas in and
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below rotor clouds
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82. the conditions most favorable to wave formation over mountainous areas are a layer of
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stable air at mountaintop altitude and a wind of at least 20 knots blowing across the ridge
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83. When flying low over hill terrain, ridges, or mountain ranges, the greatest potential danger from turbulent air currents will usually be encountered on the
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leeward side when flying into the wind
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84. Convective currents are most active on warm summer afternoons when winds are
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light
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85. During departure under conditions of suspected low-level wind shear, a sudden decrease in headwind will cause
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a loss in airspeed equal to the decrease in wind velocity
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86. During an approach, the most important and most easily recognized means of being alerted to possible wind shear is monitoring the
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power and vertical velocity required to remain on the proper glidepath
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87. What is an important characteristic of wind shear
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it can be present at any level and can exist in both a horizontal and vertical direction
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88. low-level wind shear may occur when
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there is a low-level temperature inversion with strong winds above the inversion
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89. Hazardous wind shear is commonly encountered
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in areas of temperature inversion and near thunderstorms
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90. if a temperature inversion is encountered immediately after takeoff or during an approach to a landing, a potential hazard exists due to
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wind shear
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GIVEN:
winds at 3,000 feet AGL..................30 kts surface winds.......................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
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The low level wind shear alert system (LLWAS) provides wind data and software process to detect the presence of a
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change in wind direction and/or speed within a very short distance above the airport
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