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AVIATION TRAINING BRIGADE
UNITED STATES ARMY AVIATION CENTER
Fort Rucker, Alabama
February 2009
File No. 2/5/9/9E-0525-3
PRACTICAL EXERCISE
AVIATION WEATHER COMPREHENSIVE REVIEW
DIRECTIONS TO STUDENTS: This comprehensive review covers the atmosphere and air masses, pressure
and winds, atmospheric stability and clouds, frontal weather, weather hazards, weather reports, weather charts,
and weather forecasts. You may use any publication or notes that you desire. However, on the exam,
references cannot be used.
All questions on this comprehensive review pertain to rotary-wing.
If you need help, ask the instructor.
1. The lowest layer of the atmosphere is the __________ and is approximately __________ feet at the
equator and ____________ feet at the poles.
2. What is the difference between dry air and natural air? ___________________________________
________________________________________________________________________________
3. Name the two major conditions affecting atmospheric circulation.
(1) ______________________________________
(2) ______________________________________
4. Name one semi-permanent pressure (air mass) system that causes weather over the United States.
___________________________
5. One method of heat transfer is radiation. Define radiation. ______________________________
_____________________________________________________________________________
6. What is the difference between convection and advection? ______________________________
______________________________________________________________________________
7. What is the definition of an air mass? _______________________________________________
_____________________________________________________________________________
8. What does the air mass classification code “c” indicate? ________________________________
_____________________________________________________________________________
9. What is the source region and temperature/moisture content of an mP air mass?
_____________________________________________________________________________
10. Is an air mass designated cPk warmer or colder than the surface? _______________________
11. Is a cPk air mass stable or unstable? _________________
12. Define OLR. _________________________________________________________________
13. If the temperature is increasing with altitude it is called an ______________; Two types of these are
_____________ and _____________.
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14. Polar air masses normally move in a ___________ direction and tropical air masses in a
________________ direction in the northern hemisphere.
15. Standard mean sea level pressure in “mb” millibars is __________; in inches of mercury "Hg" ________.
16. Define an isobar and its spacing on a surface analysis chart.
_________________________________________________________________________________
17. The force that starts the wind moving is the ______________ __________ ________________.
18. Pressure gradient forces always act from ___________ pressure to ___________ pressure.
19. How are isobars used to indicate strong or weak gradient forces?
_________________________________________________________________________________
20. In what direction does the wind flow around a high pressure area in the northern hemisphere?
________________________
21. How does the wind flow in relation to the isobars above the friction level (above 2,000’ AGL)?
________________________
22. What force modifies gradient force and causes the wind to flow parallel to the isobars above 2,000’?
_____________________________
23. What force is evident at the surface that causes the wind to flow across the isobars? ___________
_____________________________
24. On the following diagrams draw the gradient and surface winds.
25. Near the center of a high the air tends to SINK/RISE and in a low it tends to SINK/RISE.
26. State Buys Ballots Law. _____________________________________________________________
27. You are crabbing left to correct for a left crosswind, where is the area of lower pressure?
_____________________________
28. Water may exist in the atmosphere in three states, they are __________, ___________, and
___________.
29. Define water vapor. ________________________________________________________________
30. Water vapor in the atmosphere may begin to condense when the temperature/dew point spread is within
___________ degrees.
31. Define sublimation. ________________________________________________________________
32. The dry adiabatic cooling rate is _____ degrees per thousand feet.
33. What is the moist adiabatic cooling rate? _______________
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34. What is the level of free convection (LFC)? ________________________________________
35. What are the three conditions of atmospheric stability? ________, _________, and _________.
36. If the OLR is 4C/1000’ the air will be _________ (stable/unstable) and if the OLR is 1C/1000’ the air will
be __________ (stable/unstable).
37. The two basic categories of clouds are ______________ and ________________.
38. Which of the above categories would produce the most violent flight conditions? ___________________
39. Interpret the following cloud abbreviations.
(1) Cu ______________ (2) Cb ______________ (3) St ______________ (4) Ns ______________
(5) Sc ______________ (6) Ac ______________ (7) As ______________ (8) Cs ______________
(9) Cc ______________ (10) Ci _____________
40. Which of the clouds in the previous question would have bases below 6,500 feet?
____________________________________________________________________________
41. Define a front. ________________________________________________________________
42. The four discontinuities across a frontal surface are: (1) _______________________________
(2) _________________ (3) _______________________ (4) ______________________
43. Which, of the above discontinuities, would indicate to a pilot that the front has been penetrated while in
flight? _________________________ and __________________________________________
44. What is the primary cause of frontal weather? ________________________________________
45. Define a cold front and give its typical direction of movement.
_____________________________________________________________________________
46. If you take off in the cold air behind a cold front and climb through the frontal surface, what will happen to
the free air temperature? _______________________________________________________
47. The typical width of the severe weather band with a cold front is ______ miles and it move at an average
speed of ________ knots.
48. If a cold front is moving at a speed of 45 knots, what weather situation may form ahead of the front?
_______________________________
49. Define a warm front including its slope and direction of movement.
_____________________________________________________________________________
50. Warm front weather occurs _____________ (ahead of/behind) the surface front and may extend for
___________ miles.
51. State the cloud sequence in order if you are approaching a stable warm front from the cold air side.
_____________, _______________, _______________,__ _____________, _______________
52. Probably the most important element in flight planning for flight in a warm front is
____________________________________________________.
53. Define a stationary front. ________________________________________________________
54. The stationary front has weather similar to a _____________________ front.
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55. The winds associated with a stationary front __________________ (parallel/cross) the front.
56. In an open wave, if the air behind the cold front is the coldest of the air masses involved, a __________
type occlusion may form.
57. Identify the following frontal symbols.
58. The most violent frontal weather that pilots should probably not attempt to penetrate are the ___________
front, the _________ front, and the pre-frontal ___________ ____________.
59. Name the three atmospheric conditions necessary for all fog formation.
(1) ____________
(2) ______________ (3) ________________
60. For radiation fog, one additional factor is required, this is _____________ _________________.
61. What weather condition may cause radiation fog not to form, yet this same condition may also delay its
dissipation? ________________
62. What type fog may form when warm moist air flows over a colder surface? _________________
63. The type of fog produced by adiabatic cooling is called ____________ fog.
64. In mountainous areas, what type of fog may form as a result of cold mountain air moving down slope?
___________ _____________
65. Name the three conditions necessary for a thunderstorm to form.
(1) ______________ (2) ______________ (3) _______________
66. The two major types of thunderstorms are ____________________ and __________________.
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67. Thermal convective and orographic thunderstorms are two examples of which of the above type?
_______________
68. Which of the two major types of thunderstorms are the most dangerous to flying? ______________
69. The three stages in the life cycle of a thunderstorm are:
(1) ______________ (2) _____________ (3) _____________
70. Which of the above stages is the most dangerous and when does its cycle begin?
___________________________________
71. The ______________ stage of a thunderstorm has only updrafts and the _____________ stage has only
downdrafts.
72. What is the recommended flight procedure for scattered air mass thunderstorms? ___________________
73. The three types of ice an aircraft is subject to are: (1) __________, (2) _______________, (3)
__________________.
74. Ice formed by small supercooled water droplets is called _____________.
75. The temperature range for rime ice in stratus clouds is ____________ and in upper cumulus clouds is
_____________.
76. The type of ice formed from large supercooled water droplets is called __________________.
77. The temperature range for clear ice in clouds is ______________.
78. The most hazardous icing condition is known as ___________ ___________ and would be found under a
warm front during the winter months.
79. What are the two most important conditions necessary in the formation of aircraft icing? (1)
_______________ (2) _______________
80. The three types of clouds that may form in a mountain wave condition are: (1) _______________ (2)
_____________ (3) ________________
81. Of the three types of clouds listed above, which would be the best visual indicator of a mountain wave?
____________________
82. For helicopter flight, what is the most dangerous condition with a mountain wave?
__________________________________________________________________________________
83. What is the recommended flight procedure for crossing a mountain range if a wave condition is suspected?
________________________________________________________________________________
METAR KOZR 201255Z 18004KT 1/2SM R06/1800FT DZ FGHZ FEW000
BKN003 OVC030 25/23 A2991 RMK DZB40 FG FEW000 SLP101
SPECI KPNS 201455Z 30015G30KT 2SM +TSRA SCT010 BKN015 OVC030
29/28 A2994 RMK TSB30 RAB35 CIG014V016 SLP279
NOTE: Use the above reports to answer questions 84-93.
84. What is the ceiling at OZR? _______________________
85. What is causing the obscuration at OZR? ______________________
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86. How much of the horizon is being obscured at OZR? ______________________
87. Is any precipitation occurring at OZR and if so when did it start?
________________________________________________
88. What is the temperature/dew point spread at OZR? _____________
89. What is the RVR at OZR? ___________
90. SPECI at PNS indicates it is what type report? ____________
91. What is the ceiling reported at PNS? ______________
92. Which of the two stations has the lowest altimeter setting? __________
93. At what time did the rain begin at PNS? ___________ CST.
94. The valid time for Aviation Terminal Forecast (TAF) is ________ hours.
95. 99 on a winds aloft forecast chart would indicate
_________________________.
96. In the diagram on the right (from a winds aloft forecast
chart), the wind and temperature in the northwest section
are _______________________, and in the northeast
section are ___________________.
97. The lowest altitude covered on a winds aloft forecast chart is
___________________.
98. Surface analysis charts are issued how often?
________________
99. The source of data used on a surface analysis chart is obtained
from __________________.
100. According to the station model on the right, write the following:
(1) Sky condition ___________________.
(2) Temperature/dew point ___________.
(3) Precipitation ___________. (4) Wind ____________.
(5) Station pressure 3 hours ago _____________.
NOTE: Use the diagram on the right to answer
questions 100-105.
101. The wind direction and speed at position # 1
is _________ at _________ knots.
102. What weather hazard to flight symbol is shown at
position # 3? _______
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103. If flying at position # 4, what type aircraft icing situation would you be encountering?
______________________________
104. Position # 5 is showing what weather symbol? __________________
105. At which position, # 2 or # 3, would the weather be improving most rapidly? ___________
106. The purpose of the weather depiction chart is ________________________.
107. Shaded areas on the weather depiction chart, that may be outlined in red, indicate what kind of weather?
___________________________
Unshaded areas outlined in blue? ________________________
108. Define the weather conditions that constitute-IFR __________________________
MVFR _________________________
VFR __________________________
109. Indicate the following sky condition symbols used on the weather depiction chart.
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110. On the weather depiction chart, the visibility is normally shown to the left of
the station model. If this is not shown, what does this mean?
____________________________________________________________
111. The symbol on the right would be classified as ______________
(IFR/MVFR/VFR) category of weather on a weather depiction chart.
112. The weather depiction chart is issued every _________________ and the
data to make up the chart is obtained from _______________________.
113. The radar summary chart is issued every ______________ and its main
purpose is to _______________.
114. The following symbols on a radar summary chart indicate--
TRW
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AVIATION TRAINING BRIGADE
UNITED STATES ARMY AVIATION CENTER
Fort Rucker, Alabama
February 2009
File No. 2/5/9/9E-0525-2
PRACTICAL EXERCISE ANSWER SHEET
AVIATION WEATHER COMPREHENSIVE REVIEW
1. troposphere, 60,000, 25,000
18. high, low
2. natural air contains water vapor and
condensation nuclei
19. closely spaced isobars indicate a
strong/steep gradient; widely spaced
isobars indicate a weak/flat gradient
3. (1) uneven heating, (2) rotation of the earth
20. clockwise
4. North American High (CP) or Bermuda High
(MT) or Siberian High (MP)
21. parallel
5. transfer of heat by electromagnetic waves
22. coriolis
6. Convection is the transfer of heat vertically
via a gas; advection is the transfer of heat
horizontally via a gas.
23. friction
24.
7. a large body of air whose physical
properties (temperature and moisture) are
horizontally uniform
8. The air mass was formed over land
(continental).
9. Maritime Polar (Atlantic or Pacific Oceans),
cold/moist
25. sink, rise
10. colder
26. In the northern hemisphere, with your back
to the wind the area of lower pressure will
be to your left.
11. unstable
12. observed lapse rate, the actual change in
the air temperature with an increase in
altitude
27. ahead of you
13. inversion, nocturnal, frontal
29. moisture in the form of an invisible gas
14. southerly, northerly
30. 2C
15. 1013.2; 29.92
31. changing water vapor directly to ice or ice
to water vapor
28. liquid, vapor, solid
16. a line connecting points of equal barometric
pressure corrected to MSL; every 4 mb
32. 3C
17. pressure gradient
33. 1.5C
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34. altitude at which the temperature inside a
rising parcel of air is the same as the
ambient (outside) temperature
57. (1) warm (2) open wave (3) cold
(4) stationary (5) cold occluded
(6) warm occluded
35. stable, unstable, and conditionally unstable
58. cold, occluded, squall line
36. unstable, stable
59. (1) high moisture content; (2) condensation
nuclei; (3) a cooling action
37. cumulus, stratus
60. light wind (2-5 knots)
38. cumulus
61. overcast sky (greenhouse effect)
39. (1) cumulus (2) cumulonimbus (3) stratus
(4) nimbostratus (5) stratocumulus
(6) altocumulus (7) altostratus
(8) cirrostratus (9) cirrocumulus (10) cirrus
62. advection
63. upslope
40. Cu, Cb, St, Ns, Sc
64. valley fog
41. the boundary line between air masses of
different densities
65. (1) unstable air (2) lifting action (3) moisture
66. (1) air mass (2) frontal
42. (1) temperature (2) dew point (3) pressure
(4) wind direction
67. air mass
43. temperature, wind shift
68. frontal
44. lifting of warm moist air by cold air
69. (1) cumulus (2) mature (3) dissipating
45. the leading edge of an advancing mass of
cold air; northwest to southeast
70. mature; when precipitation begins to fall
71. cumulus, dissipating
46. it will decrease, increase, decrease
72. circumnavigate by at least 20 nautical miles
47. 50, 25
73. (1) rime (2) clear (3) frost
48. squall line
74. rime
49. the trailing edge of a retreating cold air
mass with an average slope of 1:200 and
moves northeast
75. 0C to -20C, -10C to -20C
76. clear
50. ahead, 400 to 600
77. 0C to -10C
51. Ci, Cs, As, Ns, St
78. freezing rain
52. fuel requirement to reach an alternate
airfield
79. (1) visible moisture (2) at or below-freezing
temperatures
53. any front that is moving less than 5 knots
80. (1) lenticular (2) cap (3) rotor
54. warm
81. lenticular
55. parallel
82. clear air turbulence and downdrafts on the
lee side of the mountain
56. cold
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83. Cross at a 45 angle and as high as
practical above mountain elevation.
Remain clear of clouds.
108. IFR--ceiling less than 1000’ and/or visibility
less than 3 miles
MVFR--ceiling 1000’ thru 3000’ and/or
visibility 3 thru 5 miles
VFR--ceiling over 3000’ and visibility over 5
miles
84. 300’ broken
85. fog and haze
86. 1/8 to 2/8 (FEW000)
109. (1) overcast (2) scattered
(3) totally obscured
(4) few clouds (5) broken (6) clear
87. yes, moderate drizzle, 1240Z
88. 2C
110. visibility is greater than 5 miles
89. 1800’
111. MVFR
90. special
112. 3 hours, METAR reports
91. 1500’ broken varying
113. hour, depict areas of precipitation
92. OZR
114. (1) cell movement
(2) tops of echo 44,000’
(3) thunderstorm and rain showers
93. 0835
94. 24
95. light and variable
96. 290 at 25 knots, temperature 2C, 070 at
15 knots, temperature 6C
97. 6000’ MSL
98. every three hours
99. METAR reports
100. (1) overcast (2) 16/10
(3) rain (4) NE at 20K
(5) 1011.5 mb
101. SE at 25 knots
102. thunderstorm
103. freezing rain
104. hail showers
105. 2
106. to depict areas of IFR, MVFR, and VFR
weather
107. IFR, MVFR
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