Meteorology Flashcards
(167 cards)
1
Q
AS (Cloud)
A
Altostratus
2
Q
ATIS
- Issue Times
- Heights
- Wind
- Visibility
- Cloud Type
A
- Issue Times: Irregularly, when conditions change
- Heights: feet AAL
- Wind: Degrees magnetic
- Visibility: 4 digits, in metres for less than 5000m, KM 5000m or more
- Cloud Type: Only if CB or TCU
3
Q
VA
A
Volcanic ash
4
Q
Describe Equatorial Air (Airmass)
A
Less warm and very moist
5
Q
Describe the mature stage - Thunderstorms
A
Due vast amount of water and ice carried aloft, updraughts can no longer provide enough buoyancy and moisture descends, often at high rate. Downdraughts at front portion of the Cb while updraughts continue to function at the rear. Violent turbulence zone is produced between the up and down draughts. As downdraughts hit the surface, they spread out horizontally. Freezing level oscillates, lower in the forward half of the cloud where the downdraughts prevail and higher where the updraughts are found (usually the rear). Onset of downdraughts causes precipitation in the form of heavy showers of water and often more hail. Lasts approx. 15-20 mins.
6
Q
AMD
A
Amended
7
Q
What happens to pressure before, at and after the passage of a cold front?
A
- Before: Decrease
- At: Arrest of fall
- After: Increase
8
Q
CAT
A
clear air turbulence
9
Q
SA
A
Sand
10
Q
GR
A
Hail (5mm or more)
11
Q
GS
A
Small hail (smaller than 5mm)
12
Q
Warm advection means:
A
Warm air moving toward colder regions
13
Q
METAR/METAR AUTO/SPECI
- Issue Times
- Heights
- Area covered
- Wind
- Visibility
- Cloud Type
A
- Issue Times: METARs on the hour, every hour; AUTOs every half hour
- Heights: feet AAL
- Area: Within 8km of the aerodrome reference point. If term VC is used, it applies between 8 and 16km from aerodrome reference point
- Wind: Degrees True
- Visibility: 4 digits, in metres until 9999m, 2 digits in KM above 9999m (not at AA/WN/CH)
- Cloud Type: Only if CB or TCU
14
Q
MI
A
Shallow
15
Q
Types of thunderstorms
A
- Orographic Thunderstorms
- Heat type (thermal) thunderstorms
- Convergence Thunderstorms
- Nocturnal equatorial Thunderstorms
- Cold stream (or cold advection) Thunderstorms
- Frontal Thunderstorms
16
Q
A
Drizzle
17
Q
DZ
A
Drizzle
18
Q
A
Hail
19
Q
A
Freezing Rain
20
Q
Difference between gusts and squalls
A
- Gusts: momentary increases in wind speed. Generally caused by turbulence.
- Squalls: rapid increases in wind speed lasting some minutes then dying away. Caused by weather systems.
21
Q
What happens to precipitation before, at and after the passage of a warm front?
A
- Before: Light rain turning to persistent heavy rain
- At: Rain ceases but may change to drizzle
- After: occasional rain or drizzle
22
Q
A
Widespread Fog
23
Q
What happens to pressure before, at and after the passage of a warm front?
A
- Before: Decrease
- At: Arrest of fall
- After: Steady or slightly rise
24
Q
Aquaplaning speed formula
A
Vp=9 x Square root of tyre pressure in psi
25
Dangers of icing
* Increase in Drag
* Increase in all-up-weight
* Distortion of Aerodynamic Shape
* Increase in Stall Speed
* Loss of thrust
* Pitot-Static Blockage
* Loss of Aerials
* Fuel tank vent icing
* Icing of moveable aircraft components
26
Severe Turbulence
27
9999
Visibility 10km or more
28
(blank space) (Wx symbol)
Moderate (when included before a weather phenomenon)
29
Terms on TAF:
* NSC
* BECMG
* TEMPO
* FM
* PROB
* NSC: Used when cloud is not forecast
* BECMG: Permanent change
* TEMPO: Temporary fluctuations lasting less than 1 hour
* FM: Self contained part of the forecast expected to occur rapidly
* PROB: Percentage indicating probability of weather phenomena
30
ABT
About
31
What is Virga?
What does it mean to a pilot?
* Precipitation that is evaporating before it hits the ground
* Usually occurs where the air below the cloud is very dry
* Virga associated with showers suggests strong downdrafts with possible moderate or greater turbulence
32
TL
till
33
FU
Smoke
34
HVY
Heavy
35
TAF
Aerodrome Forecast
36
AC (cloud)
Altocumulus
37
TAF/TREND
* Heights
* Area covered
* Wind
* Visibility
* Cloud Type
* Heights: feet AAL
* Area: Within 8km of aerodrome reference point
* Wind: Degrees True
* Visibility: 4 digits, in metres until 9999m, 2 digits in KM above 9999m (not at AA/WN/CH)
* Cloud Type: Only if CB or TCU
38
What is a microburst?
* A downdraft that may emerge from a cloud or no cloud as high as 15,000ft
* Wind intensifies for about 5 minutes after ground contact
* Can occur in families (more than one)
* Speed differences from 50-100kts
* Vertical speeds in excess of 3,000fpm
39
ATIS
Automatic terminal information service
40
Rain
41
Describe the Decaying (Dying) stage - Thunderstorms
Updraughts cease so general descending motion takes place. Turbulence and gusts decrease. Precipitation is common and will occur underneath the entire base of the cloud. Freezing level bulges down relative to outside the cloud.
42
Intertropical Convergence Zone
43
Describe Ac (airmass)
Arctic Continental - extremely dry and very cold
44
ST (cloud)
Stratus
45
METAR AUTO
Automatic aerodrome routine meteorological report
46
VC
Vicinity of the aerodrome
47
What happens to temperature before, at and after the passage of a warm front?
* Before: Steady or slight decrease due to precipitation
* At: Increase
* After: Light change
48
Describe Tm (airmass)
Tropical maritime - very warm and very moist
49
TIL
Until
50
Define jet stream
A strong narrow current of air, concentrated along a quasi-horizontal axis in the upper troposphere or in the stratosphere, characterised by strong vertical and horizontal wind shears featuring one or more wind maxima. Wind strength must be greater than 60 knots.
51
/// (METAR)
Cloud is detected (unable to determine TCU/CB)
52
NC
No change
53
Types of Airframe icing
* Clear ice (translucent or glaze ice)
* Rime ice (opaque ice)
* Hoar frost
* Freezing rain
54
Air masses have uniformity in: (horizontal plane)
* Temperature
* Moisture content
* Temperature lapse rate
55
FC
Funnel cloud
56
Pre-requisites for the formation of mountain waves (large scale interference):
* Mountain range of substantial dimension.
* Wind more or less at right angles to the range.
* Low level wind must be at least 15 knots and increase in strength with height.
* A generally unstable atmosphere at low levels with a stable layer at altitude, normally slightly above mountain crests.
* The air above this layer should be less stable or slightly unstable.
57
SIGMET Symbols
Severe sand or dust haze
Widespread sand storm or dust storm
WIndspread haze
Widespread mist
Widespread fog
Hail
Volcanic eruption
58
SC (cloud)
Stratocumulus
59
Widespread mist
60
What happens to precipitation before, at and after the passage of a cold front?
* Before: Not common
* At: Showers, possibly heavy, may include hail
* After: Showers may cease quickly, then isolated showers
61
What happens to visibility before, at and after the passage of a cold front?
* Before: Fair to good
* At: Very poor
* After: Very good but reduced in showers
62
G
Gusts
63
Rime Ice (Airframe Icing)
Occurs when small supercooled water droplets are disturbed and the amount of water flowing back is limited. Air pockets are trapped causing milky opaque appearance. Rime ice is rough and uneven in shape. Most likely to occur in stratiform cloud.
64
Describe Tc (airmass)
Tropical continental - very warm and very dry
65
Fohn wind requirements:
* Substantial mountain range;
* Wind blowing more or less at right angles to the mountain range;
* High moisture content of the approaching air
66
Convergence Line
67
HZ
Haze (visibility less than 5000m)
68
SG
Snow grains
69
Severe Icing
70
PS
Plus
71
Clear Ice (Airframe Icing)
Occurs when supercooled water drops are large and temperatures 0°C to -15°C. Only a small percentage of the drop freezes and a relatively large amount of water flows back. Most likely to occur in cumuliform cloud.
72
BR
Mist (1000-5000m vis)
73
MS
Minus
74
Widespread sand storm or dust storm
75
Widespread Smoke
76
Where in the vicinity of jet streams is CAT likely to be found?
The frontal zone especially at the higher levels on the cold side and just below the core. Above the jet core within the first 3-5000ft above the centre of the jet, especially on the warm side.
77
What is windshear?
* Change in wind speed and/or direction with altitude (Vertical) or in the horizontal plane (Horizontal)
* Carry extra speed on final if windshear is reported
78
PIREP
Pilot report (AIREP)
79
SEV
Severe
80
AIREP
Routine air report from aircraft in flight
81
CAVOK
Cloud and visibility ok. Issued when there is no cloud below 5000ft or minimum sector altitude, whichever is higher. No CB or TCU. Visibility at least 10km.
82
BTN
Between
83
AWIB
Aerodrome and weather information broadcast
84
Describe Pm (airmass)
Polar maritime - slightly moist and cold
85
CLD
Cloud
86
SIGMET validity time:
4 hours (6 hours for volcanic ash and tropical cyclones), reviewed after three hours or when further information is available
87
PL
Ice pellets
88
DR
Low drifting
89
FRQ
Frequent
90
What happens to wind before, at and after the passage of a warm front?
* Before: Veer and slight increase in strength
* At: Backing
* After: Fairly steady in direction and speed
91
SN
Snow
92
What happens to wind before, at and after the passage of a cold front?
* Before: slight veering and increase in strength
* At: Sudden backing may be associated with a squall
* After: Steady direction, slow decrease in strength
93
Severe Sand or Dust Haze
94
DP
Dew Point
95
SIGMET
Significant meteorological information
96
Dangers involved in flying through Thunderstorms
* Turbulence
* Up/Down draughts
* Gusts
* Wind shear
* Icing
* Lightning
* Hail
* Noise
* Loss of instruments or impairment if accuracy
97
NSC
No significant cloud
98
Cold advection means:
Cold air moving towards warmer regions
99
////
Visibility not reported
100
SIGMET Symbols
Radioactive material
Tropical cyclone
Severe Squall line
Moderate turbulence
Severe turbulence
Tropopause level
Tropopause low
101
Thunderstorm
102
DU
Dust
103
Conditions for Radiation Fog
* High relative humidity so that little cooling is needed to saturate the surface air.
* A clear sky so that terrestrial radiation can readily escape.
* A light wind so that mixing within the surface air layer is assured.
* A general stable atmosphere so that mixing and cooling are confined to a shallow layer.
104
NCD
No cloud detected
105
NS (Cloud)
Nimbostratus
106
Shower
107
WKN
Weakening
108
VRB
Variable
109
// (METAR)
Weather not detected due sensor temporarily inoperative.
110
What causes rotor streaming?
When a strong wind blows onto a mountain range and the speed of this wind decreases in strength from crest level upward.
111
+ (Wx symbol)
Heavy
112
Describe the growing stage (cumulus stage) - Thunderstorms
All draughts are upwards. Massive amounts of moisture carried aloft which turns to ice as freezing level is passed. No precipitation due severity of draughts. Raised height of freezing level. No high level stratiform development. Generally takes 15-30 minutes.
113
Requirements for the presence of thunderstorms:
* An atmosphere which is unstable through a deep layer.
* An adequate supply of moisture from below.
* A 'trigger action' which causes the initial upsurge of the unstable air.
* A mechanism that will produce sufficient electrical charge differences.
114
Severe Squall Line or Squall line (below 10,000ft)
115
Causes of turbulence
* Thermal
* Mechanical
* Shear
* Aerodynamic (Wake Turbulence)
116
STNR
Stationary
117
Difference between Radiation fog and Advection Fog
Radiation Fog involves the relatively rapid cooling of the surface, advection Fog required a surface which is already cold so that when moist air is transported over it (advection), the air can cool to temperatures lower than dew point.
118
WDSPR
Widespread
119
FZ
Freezing
120
Moderate Turbulence
121
TS
Thunderstorm
122
Freezing Level
123
AIREP Special
Special (non-routine) air report from aircraft in flight
124
Volcanic Eruption
125
Widespread Haze
126
Mountain Waves
127
BC
patches
128
T
Temperature
129
What happens to temperature before, at and after the passage of a cold front?
* Before: Steady 'warm'
* At: Often an abrupt decrease
* After: Steady 'cold'
130
Hurricane
131
Lightning
132
OCNL
Occasional
133
SPECI
Aerodrome special meteorological report
134
SIGMET Symbols
Mountain waves
Moderate icing
Severe icing
Snow
Shower
Position, speed and level of wind max.
Tropopause high
135
NSC vs SKC
NSC used at AA/WN/CH, SKC used for METAR AUTO at other airfields
136
BKN
Broken (5-7 oktas)
137
WS
Windshear
138
Tropical Cyclone
139
When is RVR passed onto pilots?
When prevailing visibility reduces below 1500m
140
PR
Partial
141
NOSIG
No significant change
142
PO
Dust/sand whirls
143
OBSC
Obscured
144
Causes for cloud formation
* Orographic Rising
* Mechanical Rising
* Convective Rising
* Widespread Ascent
* Frontal Lifting
145
- (Wx symbol)
Light
146
NSW
Nil significant weather (when expected bad weather is supposed to clear)
147
MTW
Mountain Waves
148
SH
Shower
149
Radioactive Material
150
Jet streams found in the troposphere
* Sub tropical jet - (Northern, Southern Hemisphere) (main tropospheric jet stream)
* Polar jet - (Northern, Southern Hemisphere)
151
DS
Dust storm
152
FG
fog (visbility less than 1000m)
153
Sea breezes?
* When the land heats while the water in the adjacent sea retains its temperature.
* Sets in around 10am and peaks around 2-4pm.
* Measures between 10-15 knots.
* Travels 25-40km inland, vertically 2-3000ft.
154
BLW
Below
155
SIG
Significant
156
METAR
Aerodrome routine meteorological report
157
BL
Blowing
158
TREND
* Validity time
* NOSIG
* NSW
* BECMG
* TEMPO
* TREND vs TAF
* Landing forecast is an abbreviated forecast appended to a METAR or SPECI from an international airport.
* Validity time: 2 hours NOSIG: When no significant change is expected.
* NSW: When 'bad weather' is expected to clear.
* BECMG: Gradual Change
* TEMPO: Frequent or infrequent fluctuations which lady for less than 1 hour in each instance.
* TREND supersedes the TAF during its validity period
159
TC
Tropical cyclone
160
What is a SPECI?
Term when a 'METAR' needs to be issued at a non routine time due to changes in weather conditions.
161
SQ
Squall
162
SS
Sandstorm
163
Describe Pc (airmass)
Polar continental - very dry and cold
164
What happens to visibility before, at and after the passage of a warm front?
* Before: Good but becoming poor in rain
* At: Very poor
* After: Fair but poor in drizzle/rain
165
ARFOR
* Issue Times
* Heights
* Wind
* Visibility
* Cloud Type
* Issue Times: 0530-0610, 1130-1210
* Heights: feet AMSL
* Wind: Degrees True
* Visibility: 4 digits, in metres until 9999m, 2 digits in KM above 9999m
* Cloud Type: All mid and low level cloud types
166
COR
Corrected
167
Moderate Icing
