1. Property of Lear Siegler

3. FRONTAL WEATHER
Property of Lear Siegler

4. Terminal Learning Objective Page D-1 in Student Handout:
ACTION:
CONDITION:
STANDARD:

5. Identify the characteristics common
ELO
Identify the characteristics common
to all fronts IAW FM

6. OF DIFFERENT DENSITIES.
WARM
COLD
A FRONT IS A BOUNDARY
BETWEEN AIR MASSES
OF DIFFERENT DENSITIES.
Property of Lear Siegler

7. WARM
COLD
Frontal formation: When two high pressure cells exist so that the circulation of air is converging between
them, a front is formed. The converging air currents veer
upward creating a zone (trough) of low pressure.
Property of Lear Siegler

8. cP H L mT
Property of Lear Siegler

9. A TEMPERATURE INVERSION
Frontal weather is caused by the lifting of warm moist air by colder more dense air.
ALL FRONTS HAVE
A TEMPERATURE INVERSION

10. FRONTAL DISCONTINUITIES
TEMPERATURE
DEWPOINT
PRESSURE “ FALL THEN RISE”
WIND SHIFT : APPROX 90°
DRIFT CORRECTION TO THE RIGHT
Property of Lear Siegler

11. Primary factors affecting frontal weather are slope, speed,
moisture content, and stability.

12. questions ?

13. Identify the general characteristics
ELO
Identify the general characteristics
of a cold front IAW FM

17. Property of Lear Siegler

18. Cold Front
The leading edge of a cold air mass, normally moving toward the southeast.
Property of Lear Siegler

19. Warm Front
Cold Front
Property of Lear Siegler

20. Cold Front Slope Clouds Width of weather band Winds
Direction of movement
Speed
Symbol

21. Cold Front
Slope – avg. 1:80
1 mile
80 miles

22. Cold Front COLD AIR WARM AIR COLD FRONT 25,000’ 20,000’ 15,000’
CUMULONIMBUS
20,000’
cumuliform predominant
15,000’
10,000’
COLD AIR
WARM AIR
Cold Front
COLD FRONT
Property of Lear Siegler

23. Post-frontal, can be violent
type of weather
Post-frontal, can be violent
Cold Front
Property of Lear Siegler

24. Width of weather band
50 miles
Cold Front
Property of Lear Siegler

25. northwest
southwest
Cold Front Winds

26. Property of Lear Siegler

27. 1000
996
992
Property of Lear Siegler

28. southeast
Direction of Movement

29. Average 25 knots
Speed

30. If speed of front exceeds 25 kts a squall
WARNING!
If speed of front exceeds 25 kts a squall
line may form as much as 300 miles
ahead. Squall lines may include
tornadoes, hail, and destructive winds!
Speed

32. Property of Lear Siegler

33. Property of Lear Siegler

34. SQUALL LINE
Property of Lear Siegler

35. color - blue triangle shapes, pointing in direction of movement Symbol
NOTE: You must recognize
in color and black and white.
color - blue
triangle shapes,
pointing in direction
of movement
Symbol

37. questions ?

38. a. slope -1:80 b. cumuliform clouds c. 50 mile wide band of coverage
d. winds NW behind
front, SW ahead
e. moves southeast
f knots average
speed
Property of Lear Siegler

39. Property of Lear Siegler

42. Identify the general characteristics
ELO
Identify the general characteristics
of a warm front IAW FM

43. being overridden by warmer air.
Warm Front
The trailing edge of a cold air mass, normally moving generally toward the northeast,
being overridden by warmer air.
Property of Lear Siegler

44. being overridden by warmer air.
Warm Front
The trailing edge of a cold air mass, normally moving generally toward the northeast,
being overridden by warmer air.
Property of Lear Siegler

45. Warm Front Slope Clouds Width of weather band Winds
Direction of movement
Speed
Symbol

46. Warm Front
Slope – avg. 1:200
1 mile
200 miles

47. stratiform predominant
Warm Front
Property of Lear Siegler

48. b. Stratiform clouds predominate c. 400-600 mile band of coverage
a. Slope - 1:200
b. Stratiform clouds predominate
c mile band
of coverage
d. Wind SW behind, SE
ahead of the front
e. Moves Northeast
f. 15kts avg speed
Property of Lear Siegler

51. WARM AIR COLD AIR WARM FRONT Width of weather band MILES 25,000’
20,000’
Width of weather band
15,000’ Ci
10,000’ Cs As
WARM AIR Ns St
COLD AIR
400 to 600 miles
100
200
300
400
500
MILES
WARM FRONT
Property of Lear Siegler

52. WARM FRONT
Winds
southeast
southwest

53. Property of Lear Siegler

54. WARM FRONT
northeast
Direction of Movement

55. WARM FRONT
Average 15 knots
Speed

56. WARM FRONT color - red half moon shapes, pointing in direction
NOTE: You must recognize
in color and black and white.
color - red
half moon shapes,
pointing in direction
of movement
Symbol

57. Unstable Warm Front
Property of Lear Siegler

59. questions ?

60. ELO Identify the general characteristics
of a stationary front IAW FM

61. H H Stationary Front A front which is not moving, speed
of zero to less than 5 knots. H H
Property of Lear Siegler

62. Stationary Front Slope similar to Clouds warm front
Width of weather band
Winds
Direction of movement
Speed
Symbol
similar to
warm front

63. Movement - unpredictable
Stationary Front
Winds – light and
variable, tend to
parallel isobars.
Movement - unpredictable
Speed – zero to < 5 kts H H
Property of Lear Siegler

64. Stationary Front combination of symbols for cold and warm fronts,
alternating sides of
line of front
NOTE: You must recognize
in color and black and white.
color – alternating
red and blue
Property of Lear Siegler

65. questions ?

66. Identify the general characteristics
ELO
Identify the general characteristics
of an open wave IAW FM

67. Open Wave L
A wave-like appearance with one portion a cold front and the other a warm front with an open area in between.
Property of Lear Siegler

68. Vertical cross section.
Open Wave
Warm Air
Colder
Cold
Vertical cross section.
Property of Lear Siegler

69. Stationary Front
Mostly forms along a stationary front, but may form from any existing front. L
Property of Lear Siegler

70. Open Wave L
Property of Lear Siegler

71. L
Cold Front
Warm Front
Property of Lear Siegler

72. Open Wave L
Property of Lear Siegler

73. Open Wave L
Property of Lear Siegler

74. Open Wave L
Property of Lear Siegler

75. L Open Wave Weather Warm front WX Cold front WX Warm air
Property of Lear Siegler

76. direction along the line of
Open Wave L
Movement
Travels in easterly
direction along the line of
the original front
Property of Lear Siegler

77. Weather chart portrayal
Open Wave L
Warm front
Weather chart portrayal
Cold front
Property of Lear Siegler

78. A B
Property of Lear Siegler

79. Property of Lear Siegler

80. questions ?

82. ELO Identify the general characteristics
of an occluded front IAW FM

83. Occluded Front:
The result of a faster moving cold front overtaking a slower moving warm front.
The effect is one front on top of the other
squeezing warm air between.

84. Warm Air Colder Cold Open Wave Occluded Front:
The result of a faster moving cold front overtaking a slower moving warm front.
The effect is one front on top of the other
squeezing warm air between.
Property of Lear Siegler

85. Warm Air Colder Cold Open Wave 25 kts. 15 kts.
Property of Lear Siegler

86. Open Wave
Warm Air
Colder
Cold
Property of Lear Siegler

87. Cold Occlusion
Warm Air
Colder
Cold
Property of Lear Siegler

88. Cold Occlusion
Warm Air
Colder
Cold
Property of Lear Siegler

89. Two types of occlusions:
Cold front occlusion – The cold front
runs underneath the warm front.
(coldest air is behind the cold front)
Warm front occlusion – The cold front
overruns the warm front.
(coldest air is ahead of the warm front)

90. Warm Air Colder Cold Open Wave Cold front occlusion – The cold front
runs underneath the warm front.
(coldest air is behind the cold front)
Warm Air
Colder
Cold
Property of Lear Siegler

91. Cold Occlusion
Warm Air
Colder
Cold
Property of Lear Siegler

92. Cold Occlusion
Warm Air
Colder
Cold
Property of Lear Siegler

93. Warm Air Cold Colder Open Wave Warm front occlusion – The cold front
overruns the warm front.
(coldest air is ahead of the warm front)
Warm Air
Cold
Colder
Property of Lear Siegler

94. Warm Occlusion
Warm Air
Cold
Colder
Property of Lear Siegler

95. Warm Occlusion
Warm Air
Cold
Colder
Property of Lear Siegler

96. Occlusions: cloud types
Both warm and cold front types
stratiform and cumuliform

97. Occlusions: weather Weather associated with each of these fronts
combines widespread low ceilings and poor
visibilities of the warm front with the severe
weather of the cold front.

98. Occlusions: winds Ahead of the occlusion vary south to east
generally from the southeast,
behind the front generally from the northwest.

100. Similar to an open wave, to the east
Occlusions: movement
Similar to an open wave, to the east

102. direction along the line of
Cold Occlusion
Travels in easterly
direction along the line of
the original front
Property of Lear Siegler

103. Portrayal:
cold occlusion

104. Warm Occlusion
Portrayal:
warm occlusion
Property of Lear Siegler

105. questions ?

106. ELO Identify the proper flight procedures to use when dealing with
frontal weather IAW FM

107. Each type front presents certain problems to the aviator. The aviator
RECOGNITION OF TYPE:
Each type front presents certain problems to the aviator. The aviator
must learn to recognize type of front in
order to apply proper procedures.

108. FLIGHT CONSIDERATIONS:
Cold fronts and squall lines
DON’T GO!

109. FLIGHT CONSIDERATIONS: Warm fronts
Sufficient fuel for a long flight and possible
diversion to an alternate airfield

110. FLIGHT CONSIDERATIONS: Stationary fronts
Same as warm front, plus
alert for open wave and occlusion

111. FLIGHT CONSIDERATIONS: Open wave
Avoid the crest of the wave and
cold front, cold front procedures
for cold side, warm front
procedures for warm side

112. WARNING! FLIGHT CONSIDERATIONS: Occluded fronts
Occluded fronts offer worst possible weather! Avoid the apex
of the occlusion by at least 50 to 100 miles.
Circumnavigate to right (tailwinds). Do not fly through an
occluded front. Wait, circumnavigate, or fly through
stationary/warm front separately.

114. questions ?

115. Identify indications of frontal
ELO
Identify indications of frontal
passage IAW FM

116. On the ground
wind shift
Temperature
Dew point
pressure

117. In flight more difficult to recognize best indicator is OAT gauge
anticipate drift correction to right
(with possible exception of
occlusion)

118. Property of Lear Siegler

119. Property of Lear Siegler

120. Property of Lear Siegler

121. Property of Lear Siegler

122. Property of Lear Siegler

123. Property of Lear Siegler

124. Property of Lear Siegler

125. Property of Lear Siegler

126. questions ?

128. Open Wave
Warm Air
Colder
Cold
Property of Lear Siegler

131. Practical Exercise

132. The end