Meteorology Flashcards
(354 cards)
1
Q
The out-flowing in a mature thunderstorm
A
Usually is greater in the direction of the thunderstorm
2
Q
Why is the temperature colder in polar region
A
The solar radiation is lesser per unit area as compared to the tropics
3
Q
What is a visual sign of a mature thunderstorm
A
Cumulus growing over layered clouds like stratocumulus or altocumulus
4
Q
There is a sea Breeze in the late morning of a summer. Which of these will explain what happens to the surface conditions above the land when the wind moves across?
A
Temperature will drop, dew point will increase
5
Q
How is an airmass created?
A
When air remains stagnant over land or sea and develops similar properties
6
Q
Which is true of polar front jet streams
A
They are located in the warm sector and are ahead of the frontal area at latitudes of 40-50deg
7
Q
Questions asks about how is hail generated
A
Option chosen was the one that says strong updraughts in CB, with most of the cloud above freezing level and with supercooled water droplets.
8
Q
How is SWD formed
A
… due to lack of freezing nuclei, the water remains in unstable state below 0degC as SWD
9
Q
Image shown of flight from HK to SG. They ask what is the average wind speed at 5N
A
070/40, -53degC
10
Q
Which of the following will most likely lead to the formation of Low level stratus clouds
A
Moist air moving over a relatively cooler sea, with wind speeds in excess of 15kts
11
Q
How do you distinguish cumulus clouds
A
Segregated segment of clouds….
12
Q
Rime ice
A
Instantaneous icing with small SWD
13
Q
Which of this is the correct code used in METAR?
A
GR: Hail or big snow, precipitate with diameter more than 5mm
14
Q
Wind shear at a friction layer is most pronounced when
A
Density of friction layer is maximum just before dawn
15
Q
What is conduction
A
“… in direct contact with each other and at different temperatures so there is some heat transfer…”
16
Q
After passage of warm front, 1 hour later you are in the warm sector. What would you expect to see in the warm sector?
A
More or less constant QNH, light and intermittent rain, Low and extensive clouds, Low vis
17
Q
In the SH, where do trade winds originate from
A
From sub tropical high belt, and move from SE
18
Q
What’s the expected weather like in South Asia under the SW monsoon?
A
Option with most severe conditions.
Heavy turbulence, thunderstorms, etc
19
Q
What’s the length of jet stream
A
2000nm
20
Q
Definition of subsidence inversion
A
When air sinks, it heats up adiabatically…
21
Q
Anti-cyclonic at the surface, cold surface, how to pressure levels appear
A
Bulges down, and decrease in strength as altitude increases
22
Q
Bergeron theory of rain formation
A
Some supercooled water droplets will turn to ice and grow by sublimation and fall as snow or rain, depending on temperature
23
Q
Weather conditions for blocking high systems
A
Good weather for Long time
24
Q
What type of wind shear may be reported in a METAR
A
All reported wind shear
25
What is a mistral
A valley wind
26
RVR measured in
Metres
27
Tornadoes are formed by
Strong up currents within CB
28
Which of the following best describes the formation of tornadoes
Strong updraft within CB
29
There is Low pressure near the surface and there is some pressure aloft. Does it bulge up or down
Bulge down rises and reduces in size
30
When is diurnal variation the greatest?
Mid-afternoon
31
Diurnal variation of relative humidity
RH decreases by day, increases by night
32
FL180 which charts do you use
500hPa
33
What is true altitude?
Actual altitude above AMSL
34
Given FL330, calculate true altitude if ISA deviation is +7degC
33924ft (closest is 34000ft)
35
Which is the severe most quadrant for the Cyclones in the SH?
Left front quadrant
36
Pressure gradients are measured for practicality purposes
From high to Low pressure
37
Pressure gradient is measured
Perpendicular to isobars
38
What is the weather at a Col
Not much weather
39
What is the weather around a Col in winter
Low vis and fog
40
What weather can you expect in Col winter
Light winds, fog...
41
What is set on AC altimeter if it shows 0ft on the ground
QFE
42
What affects the type of icing
Type of droplets, water vapour content and air temperature
43
What are the conditions to clear ice formation
When droplets are large
44
When an air mass goes to a warmer area what happens
Becomes unstable, convection occurs, Cu Cb form in day with good vis
45
Why is SALR lower than DALR
Due to heating caused by condensation and release of latent heat
46
Why are poles colder than equator
Due to sun more directly overhead equator than poles
47
Solar radiation is reflected back to space due to
Clouds
48
What are the weather phenomena indicating an area of jetstreams
Cirrus streaks, change in wind speeds and CAT
49
What are the met signs that you are approaching a jet stream while flying
Change in temperature, winds and drifts, CAT
50
Which area of jet stream would you experience the worst CAT
Core to the Low pressure side
51
Severe turbulence is
Large and abrupt movement of AC in the 3 axes, pilot losing control of AC definitely, but briefly, and loose articles gets tossed
52
What is an AIRMET
MET info along air route
| Info for met conditions
53
Geostrophic wind is the balance of what
Coriolis and pressure gradient force
54
What is an orographic depression
Flow of air meets mountain range at large angle , causing air to flow around, instead of over the TOP
55
During months of June to September, where is the wind coming from Singapore
S and SW monsoon
56
What are tradewinds characteristics
Steady, 10kts
57
An air mass at its origin is
Stable
58
What happens to the winds and pressure when a warm front passes you
It veers
59
Size of drizzle
0.2mm to 0.5mm
60
In what units is wind reported in TAF and METAR
True/kts
61
What is the weather in a quasi-stationary front
Little/no weather
62
Where will the TU be at 100Z
22. 440 to 118.00
| 224. 40 to 11.800
63
During the summer of SH where do you expect the ITCZ to be in the South Pacific
Mainly below equator but slightly above in central South Pacific
64
Why is the main cause for general circulation
Transfer of heat from equator to polar region
65
What is the average altitude and temp of tropopause for tropical regions
55000' to 60000' , -70degC
66
The tropopause over the equator is at FL_____, while it is at FL_____at the poles. Compared to the poles, the tropopause at the equator is
520, 280, colder
67
The tropopause height is higher
Over the equator and the temperature is colder
68
```
260/55
250/75
Variation 9degE
TAS 457kts
Find the true heading
```
220deg / 410kt
69
Where does the Harmattan blow to
Hot, dusty winds blowing across Sahara desert
70
Where does the cirrus cloud form at a jet stream
Below towards warm side
71
What weather is expected when tropical maritime air blow towards U.K. or Europe during winter
Fog/Stratiform
72
What weather can you expect when passing through a cold front in NH
Steady or slight veer to NW, Cu Cb
73
You left your aircraft for 3 hours coming back after to find your altimeter reading has increased. What is the likely reason?
QNH decreased
74
Where is a RVR reading taken from
Specific location and down one direction
75
The met measurement of RVR is described as
Distance measured by an electronic device where intensity of light a known distance away is measured by a photoelectric cell
76
Which would be a correct instrumented RVR reading
R20R/300U
77
RVR 400 450 500. Where are they measured?
Touchdown, midpoint, end-point
78
Cyclone formation in the South Pacific between the meridian
140E 160W
79
Tropical cyclones in the SW Pacific usually occurs
Between 5degS and 20degS
80
Where are the tropical storms found in the Pacific in the Southern Hemisphere
5-25 degrees South, 140W to 160E
81
A thermal wind is
Affected by Buys Ballot Law and blows to the right when moving from an area of Low pressure to High pressure in the SH
82
The ozone layer
Absorbs UV radiation and warms the atmosphere
83
Which of the following corresponds to Koppen's climate classification
```
A: Tropical
B: Arid/Dry
C: Temperature (warm)
D: Continental (snow)
E: Polar
```
84
Where will wake turbulence be encountered
Below and just behind the flight path of a clean, heavy aircraft flying at Low speed
85
What is the ISA condition at sea level
15degC, 1013hPa
86
A high level chart with height specific isobaric levels is known as
A constant pressure chart
87
What is the rate of accretion of icing over mountains like?
Heavy because atmosphere is disturbed due orohraphic effect
88
Why icing risk is higher in orographic lifting
Air being forced up contains more supercooled water droplets
89
When will you expect a wet monsoon to occur over Singapore?
Oct - Mar (or Jan-Mar)
90
What happens when a given parcel of air is cooled?
Relative humidity increases, dew point & absolute humidity remains the same
91
What are the required conditions for the formation of TRS
Water 27degC, <1000hPa, convection
92
Surface chart with a high to the left of Ireland and Low over north west France. Determine direction of surface wind
030T
93
In summer over British isles, what sort of weather will you expect with a tropical continental air mass
Warm or very warm weather with dusty conditions
94
A jet stream is formed from a
Horizontal temperature difference
95
What causes nocturnal thunderstorms in the tropics
The sea is being warmed and air cooling at night
96
What triggers precipitation in the air masses
Orographic lifting and convective currents
97
With respect to jetstreams, what are the relative height of a tropopause
The tropopause is higher on the tropical side than the polar side
98
For which altitude would you use a 500hPa chart
FL180
99
Refer to figure above, what is the flight level you can expect CAT along the flight path from Sydney, in red?
FL250 - 530
100
Refer to figure above, what is the approx speed of the jet stream you can expect when flying at FL390 along the flight path from Sydney, in red?
160kts
101
Refer to figure above, what is the tropopause height along the flight path from Sydney, in red, towards Hong Kong?
FL420 - 500
102
With high level of divergence, air at the surface would,
Converge and ascend
103
With high level divergence, air at the surface would
Diverge and descend
104
Refer to the figure above, what is shown
| A curve with semi circles on TOP
Warm front
105
Which of the following represents a squall line
------ .. ------- .. -------
106
In a blocking high in the South Pacific, the vertical profile would be
Weak divergence at lower levels and strong convergence at high levels
107
What happens in a blocking anticyclone
Subsidence, intense in upper troposphere, weak in lower troposphere
108
Where can info about volcanic ashes in the atmosphere be found
In SIGMET and in ACCA notices
109
Volcanic ash advisory is reported to who / goes to who
Pilots
110
What does the above symbol represents on a weather chart
| Looks like a bell, with 3converging sticks on TOP
Volcanic eruption
111
Which conditions best promotes the development of radiation fog
Night time or dawn with clear skies, light wind and high relative humidity
112
What does advection fog form
Over cold land or sea with warm moist air
113
When temp is said tone ISA +2degC, it means
At the pressure altitude, temp is 2degC warmer than ISA temp typical of the altitude
114
Diff between FL and altitude
FL is constant pressure level and altitude is constant distance from MSL
115
On which surface will ice accretion occur first
Leading edge of tailplanes and aerials
116
First aircraft icing most likely to be
On wings upper and lower surface
117
How does surface and speed affect the rate of ice accretion
Sharp surfaces at high speed increase accretion rate
118
Which of the following is correct
| About two letter code
GR: Hail, iceballs of diameter greater than 5mm
119
Which of the following does not favour the formation of standing mountain Lee waves
Winds varying direction as altitude changes
120
What factors are required for standing waves
Low level 15kts and increasing with altitude and a stable layer above the ridge blowing nearly or perpendicular to the ridge
121
The following is a forecast at an aerodrome
Tons of numberssss
Local magnetic variation is 20degW. If you are flying inbound on a holding pattern at 5000' at 100degM, what will be the headwind component
-10
122
Geostrophic wind is caused by
PGE, coriolis force
123
Coalescence theory is
Assumption presence of the range of droplets sizes larger falling faster to meet smaller droplets and fall as rain
124
Bergeron theory is unable to explain the formation of precipitation uncertain cases because
Not all water droplets are supercooled
125
In an occluded front
Cold air behind the cold front undercuts the warm air and cold air ahead of the warm front , and it is called a cold occlusion
126
What is the weather at a cold occlusion
Embedded Cb. Most of the precipitation is behind the surface position of the occlusion
127
Low level wind shear associated with the Top of the friction layer will be at its
Maximum when layer density is greater before dawn
128
Main diff between microburst and downburst, is that microburst
Can only occur singly
129
Virga is
Rain that sublimates before reaching ground, absorbing latent heat and cooling surrounding air
130
In convective clouds
Saturated air is cooled, water vapour condenses, releasing latent heat, heating the cloud relative to surrounding air and intensifying the convective effect
131
Water vapour in air
Cannot be seen as it is a gas
132
At 40degN latitude, the prevailing wind is
Westerly
133
At 3000ft just above a Low level inversion, what kind of cloud do you expect
CB
134
Flying at 3000ft in cloud, you experience light turbulence and light icing, from which cloud is this the most common
SC
135
How is radiation fog lifted
Insolation
136
What are the conditions that favours radiation fog to dissipate
Insolation and strong wind blowing the surface
137
What causes year round thunderstorms in the tropics
ITCZ
138
The tropopause can be defined as
Where the decrease in temp with altitude ceases
139
When a particle is struck and part of the solar radiation is reflected back to space and part of it warms the atmosphere, this is known as
Reflection
140
How does the wind direction and strength change from surface to upper levels in the Southern Hemisphere
It is constant in the friction layer but suddenly increases speed and backs above the friction layer
141
At 18Z, where is TS PACHU expected to be at?
22.32N 116.00E
142
Low temp will
Increase density and pressure lapse rate
143
What happens when increase in temp to density and pressure lapse rate
Both decrease
144
What measures the cloud base
Ceilometer
145
Occlusion in a synoptic chart will show triangles
And half circles both drawn on the side towards the advancement of the front
146
What info would you expect to see in a VOLMET
Visibility
| Wind shear
147
What are the requirements for lenticular clouds to form
Stable moist air flowing over mountain with dryer air
148
What causes lenticular clouds
Mountain waves in the Lee of the mountain range
149
Why is CAT normally found in the vicinity of jetstreams
Because of the horizontal and vertical wind shear
150
Why is there an inversion in the higher atmosphere
The reaction of the ultraviolet radiation and the ozone layer
151
Why temp is constant with the increase in altitude at stratosphere
Due to absorption of UV light by ozone molecules
152
QNH is
Set when aircraft below transition altitude
153
What is area R
Col/Flat pressure area
154
What do you call an area of pressure with 2 anticyclonic pressures and 2 Low pressures
Col
155
A trough is a system of
Low pressure and the pressure is lower in trough than on both sides
156
A trough is an _____ of an area of Low pressure with characteristics
Extension
Similar to its parent Low
157
A ridge is an area of
High pressure with the pressure on both sides of the extended centre lines of the ridge lower than in the ridge
158
The action of solar radiation being returned to upper atmosphere is
Reflection
159
What is a sign of mid level stability
Altocumulus castellanus
160
What happens during cumulus cloud formation
Condensation causes latent heat to be released, warming the surrounding air and causing an increase in rising effect
161
What is displayed when the altimeter is set to 1013mb
Pressure altitude
162
A gust is
Rapid increase in wind strength lasting less than 1 minute
163
What causes rime icing
Small supercooled water droplets
164
What order of clouds would you expect to see ahead of a warm front
Ci, Cs, As, Ns
165
What type of cloud is layered and dark, producing extensive precipitation
Ns
166
What cloud brings about heavy showers
Cu, Cb
167
Subsidence inversion is
As the air descends, it will be heated adiabatically and will be warmer than the air at a lower level
168
When there is more water vapour in the air, the dew point
Increases
169
The Fohn wind is
Warm dry air blowing on the Lee side of a mountain
170
Upcurrents in a thunderstorm
Predominates the growing stage
171
Oktas are measured in terms of
Eights
172
When temp falls, becoming colder
Density increases, pressure lapse rate increases
173
Intermittent rain will be most common to which type of cloud
St, Sc
174
What type of icing may occur during a rapid descent
Hoar frost
175
With a wind speed of 34kts and The Eye developed - What stage of TRS
Mature
176
Lines on a chart showing areas of equal temperature are known as
Isotherms
177
In the mature stage of a thunderstorm
Both up and downdraughts with downdraughts restricted to the front part of thunderstorm
178
A cold front is depicted on a contour chart
By a boundary on the surface between air masses
179
What weather can be expected when polar maritime air flows over a colder region
Light precipitation
180
Why is there no icing hazard when OAT is below -30degC
At those temp, there is less supercooled water droplets and most of the precipitate is dry ice crystals
181
Tropical cyclone advisory service is
To monitor tropical cyclones and advise to met offices
182
METAR wind is given in
True
183
TAF VHHH 211700Z 2118/2300 ______ how Long is this TAF valid?
30 hours
184
The temp is constant and you fly to a Low pressure area. What happens to the indicated altitude
Over reads
185
Fly from area of high pressure to Low pressure, what will your altimeter indicate
It will over read
186
What happens to the surface wind over the sea in the Northern Hemisphere
Speed decreases by 30%, and backs by 10deg
187
CF and PGF act
Opposite to each other
188
In a lenticular cloud, ice is formed
At a slow rate as lenticular clouds generally have fair weather
189
Clear ice at temp of 0degC to -15degC are common due to
More large SWD
190
Which is reported in PIREP/AIREP
Moderate icing
191
Which observed conditions would require special aircraft observation to be made
Volcanic activity
192
In the SH, where do the trade winds blow
From sub tropical high SE
193
Flying over Singapore in July
Winds are easterly
194
Once it first hits the ground, a downburst will typically last about
5-30 minutes
195
Orographic Low
Occurs on the Lee side of the mountain, bad vis, cloudy skies
Leeward side, bad weather all blown to the other side
196
Orographic thunderstorms
Usually stays over area of development
197
Terrestrial radiation heat transfer
Due to earth absorbing and emitting sun's radiant energy and sending it back to space
198
Atmospheric inversion is
Temp increases with height
199
Ozone at high levels
Absorbs sun radiation and warms atmosphere
200
Thermal thunderstorms in the day in the tropics are due to
Convergence of ITCZ
201
Thermal heating in the tropics causing rain due to
Convergence of ITCZ
202
Mechanical Turbulence
Increasing with decreasing ELR
203
Length of warm sector
150nm
204
The transition between cold air and warm air in the warm sector is
25 - 120km
205
Weather behind active cold front
Cu, poor vis and turbulent
Cu and Cb cloud, heavy showers, poor vis
206
In front of a cold front
Calm with excessive ST
207
Frontal thunderstorms greatest activity
Cold front is rapid and very cold
208
In general, the intensity and activity of frontal thunderstorms are greatest with
Cold fronts which moves at a rapid rate
209
Effect of smoke particles on condensation
Occurs more readily
210
Fohn wind strong moist air blowing at almost right angles to mountain range
Light winds at Low altitude; strong winds higher up
211
Characteristics of Fohn wind
Dry and warm katabatic wind flowing down LEE side of the mountain
212
Thermal thunderstorms occur
Mid early to mid afternoon, sometimes lasting into evening
213
State reason why water vapour is less dense than air at constant temp
Air is heavier than water
214
Dry air and moist air at constant pressure and temp. Which is denser
Moist air is less dense than dry air
215
Compare dry air with saturated air
Dry air heavier than saturated air
216
Is air with more water vapour less dense
True. Water molecules have less mass than air molecules
217
TRS occurring in SW occurs _____ times from the months ____ -_____
8
12-4
218
As air temp increases during the day of 'settled weather', the base of the convective cloud
Rises
219
What cloud type does convection give rise to
Cumulus
220
During cycle of thunderstorm, the stage during which freezing air bulges down relative to level outside is
Mature stage
221
What conditions is most ideal for high altitudes contrails to prevail in atmosphere
Air that is saturated with water vapour, which speeds up sublimation
222
Where are the light easterly waves found
10N - 20N
223
What absorbs the sun radiation before before hitting the earth surface. Why is there a temp inversion in the stratosphere
Ozone absorbs ultraviolet, water vapour absorbs infrared
224
Process where increase in temp due to addition of heat energy from external heat source
Non-adiabatic
225
At what pressure can you find the artic or polar jet stream
300hPa
226
Polar jetstream in terms of polar front
On top of surface front
227
At which stage of thunderstorm will there be downdraughts
Mature
228
Who is the function of world area forecast system for
For all aeronautical users
229
What is the weather over Azores High
Tropical maritime
230
Given observed temp over Singapore is -54degC. Given a map of FL390. What is the ISA deviation
+3degC
231
Study the isobar patterns above. What is true for the image above in the Southern Hemisphere
If wind is easterly at C-D, the region C-D depicts a trough and A-B depicts a Ridge
232
What forms drizzle
Stratus clouds with Low winds
Weak updraughts into shallow layered cloud
233
Blocking anticyclone blocks _____ movement of system and it occur when zonal index is_____
Eastward, High
234
Land Breeze
In a summer night, land is cooled a little bit
235
Land Breeze. When and how it happens
Happens at night. When land cools and pressure is higher on land, resulting in air to blow from land to sea
236
Which statement is true for CF and PGF
PGF goes high to Low while CF is always right angles to wind direction
237
What does pulse radar Doppler detects
Particle speed
238
Which type of clouds gives the most icing
Cumulonimbus
239
Airplane below cloud of supercooled water droplets but above freezing level, when it levels off will there be icing? (Some diagram shown)
Freezing level is below cloud, the aircraft will cruise between cloud base and the freezing level
Yes there will be significant icing in freezing rain
240
Volcanic ash is advised by
VAAC
241
Winds above friction layer in Southern Hemisphere
Not much variation until out of friction layer, then increase and back
242
Which air mass would result in dry and cold air
Continental polar
243
What altitude for tropopause in tropical region
16km, 48000ft (should be around 55000ft)
244
What precipitation does stratocumulus has
Light rain/drizzle
245
Gradient wind vs Geosptrophic wind around area of Low pressure
Geostrophic wind more than gradient wind
246
Sea Breeze: North facing coast with a slack pressure gradient over the area. Where do you expect the wind to be from, on a hot sunny day
360deg / 15kts
247
What is the effect of carbon monoxide in the atmosphere
Absorb Long wave radiation
248
How should a pilot adjust pressure setting
Use elevation of airfield if QNH not given
249
In which conditions is the turbulent layer thickest
What causes mechanical turbulence
Strong winds, large buildings, rough surface, unstable air
250
A warm front is
Warm air displacing cold air
251
What weather would your expect with an approaching warm front
Precipitation increasing in intensity, then after the front passes, intermittent showers
252
Passage of warm front
Wind veers.. pressure falls... dew point and temp increases
253
A warm front just passed you, 1 hour later?
Steady QNH, various with Low clouds, intermittent drizzle
254
What weather behind a warm front
More or less constant QNH
255
What sort of clouds observed behind a warm front
Altocumulus, cumulus, clear skies
256
What is conduction
Air molecules that have different temperature interact, and sensible heat is transferred
257
Anticyclone has what
Low surface wind, subsidence at high troposphere
258
____ forces air to rise and the surface friction prevents____
Divergence, Convergence
259
An air mass that is warm, extremely Low relative humidity, lapse rate greater than DALR, what kind of air mass is that
Tropical continental
260
During terrestrial radiation, what is the process
Conduction and convection
261
What is the main mechanism of orographic fog
Air being forced up mountain
262
Why is visibility dependent on illumination from sun or moon
Visibility due to transparency in air
263
How does surface wind and humidity affect rate of evaporation of water
Warm, dry, high wind speed, Low atmospheric pressure increases the rate
264
Orographic lifting: How does it occur
Only when wind blows more or less at right angles
265
When will clear ice form on airframe
Clouds consisting of mainly of large supercooled water droplets at temperature 0degC to -20degC
266
Polar front jetstreams occur at
45-65
267
When is subtropical jetstream the strongest
During winter
268
Which of these conditions are most favourable for formation of TRS
High relatively humidity, convergence at lower levels and divergence at the top
269
Jetstreams usually have the following similar characteristics
A strong horizontal temp gradient, and located near a large difference in the tropopause height
270
What is the visibility in fog
Less than 1000m
271
Which of these is a correct RVR reading
R05 / 800D
272
Initial stage of thunderstorm characterised by updraughts causing condensation
Releasing latent heat, making cloud warmer than surrounding areas, and making it grow stronger
273
What is the main cause for Long line of weather along the ITCZ
Convergence of NE&SE tradewinds
274
ITCZ convective clouds formed by what
Convergence of tradewinds
275
In the Southern Hemisphere, tradewinds tend to blow from
SE
276
Trade winds blow from
Sub tropical high pressure belt
277
How are hails formed
Strong updraughts in CB
278
The movement of quasi-stationary front is
No movement across warm and cold front
279
The warm or cold front labelled on weather map takes reference from
Separation between air mass at the surface
280
Where can mid-latitude climate zone be found
Western region of continent between 40-60 degrees
281
What is the QFE definition based on ICAO
Airfield pressure
282
The Sumatra Squall in Southeast Asia occurs during
SW monsoon, May-Aug
283
Who is responsible for global weather and upper wind charts
WAFC
284
What is zero kelvin equivalent to degree Celsius
-273
285
Low level turbulent wind and its associated clouds are
Stratus
286
Refer to figure above. With reference to the diurnal variation of temp over 24hours, what is the time at the point marked below
(Looks like a sound wave diagrams)
Early evening
287
In tropics, frequent thunderstorms that occur in the afternoon, all year round, is known as
Heat (Thermal) thunderstorm
288
An aircraft is set to SPS. Airfield is 1000ft AMSL with QNH at airfield of 1020hPa. Surface temp is 15degC. What will the altimeter read when the aircraft is on the ground at the airfield
890ft
289
What is the minimum speed required for a moving air mass to be considered a jetstream
60kts
290
How is the wet bulb temp at saturation related to the dew point
Equals to
291
Refer to figure above. An airplane is taking off in the direction of a thunderstorm as shown below. The flight path is labelled by the red line. Describe the wind experienced by the airplane at stages 1, 2 and 3 of the path
(Sibei complicated drawing with clouds)
Headwind, Windshear and turbulence, tailwind
292
Why do you reset altimeter
Reads pressure, therefore changes with sea level
293
How do you get supercooled water droplets
Orographic lifting of an air mass past the 0deg isotherm causes water droplets to become supercooled
294
SW monsoon in India will result in what weather
Cloudiness + Heavy precipitation
295
What are the typical weather conditions in SW monsoon
Intense instability, severe weather
296
Tradewinds absorb a lot of water over warm equatorial oceans and
Become "rain bearing" winds
297
In mid latitudes, what are altocumulus made of
Both supercooled water droplets and ice crystals
298
What is DALR
3deg/1000ft
299
RVR measured by
Transmissometer
300
Aircraft is departing an airfield in the SH and intends to fly through the friction level, what does he encounter
A speed up by 50% and backing by 30deg
301
A parcel of air has water content of 4g/kg. The air can be saturated to 5g/kg. What is the relative humidity
80%
302
A chart contains contour lines of equal height. The line is
Isohypse (same heights)
303
There is a depression with a cold core, the pressure level
Pressure level bulges down, system weakens with altitude
304
What does an observer on ground notice when a thunderstorm is inside a thick cloud/Cb in embedded clouds
Hail
305
Clear ice is typically formed with what kind of cloud form
Cumuliform
306
Updraughts in thunderstorm is usually
In growing stage
307
Hot and humid morning in the tropics
Thunderstorm in the afternoon if moisture is spread out and ELR is favourable
308
Polar jetstream is found at ___ of the tropopause high and ____ of the polar front
Equatorial ; Polar
309
Direction of Tropical revolving thunderstorm in is lifetime?
| Diagram that has 2 halves, bottom half looks like spider web
Away from equator, westwards
310
As air temp rises, cloud base would
Rise
311
____ due to pressure loft, surface friction decreases ___ . This lowers the mean sea pressure
Divergence ; convergence
312
The fastest winds of a TRS (SH) are found
Around The Eye
313
In a Low pressure system, ____ is aloft and friction will slow the rate of ____ of the air below
Divergence ; Convergence
314
What cloud is icing the least likely
Cirrus
315
When will thunderstorms occur
Thunderstorms will occur in the afternoon provided that moisture content and lapse rate are favourable
316
What is an AIRMET
Weather message for Low level hazardous conditions
317
Air which is warm, Low relative humidity and ELR higher than DALR
Tropical continental
318
Warm front is likely to develop when
Warm air replaces cold air
319
Define Saturated vapour pressure
Pressure of water vapour above a surface of water
320
Definition of Monsoon wind
Rain bearing wind over Asian continent
321
Pressure altitude is ____ true altitude
Imaginary Datum, MSL
322
Which is the best description for a SW monsoon over South Asia in summer
Large scale sea Breeze bring heavy precipitation/shower
323
When flying over near a TS where is the most severe icing
6-8000ft above freezing level
324
Contour line on chart is based on
Pressure alt AMSL and sea level pressure, based on Atmospheric Temp
325
Flying behind a cold front
Cumulus cloud, poor vis
326
Polar jetstream is located on the ____ of the tropopause break and the ___ of the polar front
Equatorial side ; polar side
327
The stage of the thunderstorm which contains only downdraft
Mature
328
What is friction layer
The layer of air near earth surface which is due to the roughness of the surface
329
4 stages of TRS
Convergence of wind along equatorial region -> smth -> TRS
330
The tropopause is at its
Highest in equatorial region and its temp is the coldest
331
Air mass in Antarctica is what kind
Artic continental
332
Inversion layer
Vis better above, temp increases with height
333
5 stages of TRS
Tropical disturbance, depression, storm, severe storm, TRS
334
What is convection
Air warmed by forest fires
335
Which is anticyclone
Cold cove
336
Altocumulus at mid level
Ice + water droplet
337
What's the wind velocity at F310 165E? Data retrieved is 28052M47
280deg true, 52kts
338
What's the kind of precipitation in NS
Steady... continuous rain
339
Air is descending adiabatically
Density decreases, temp increases
340
What is the relative humidity in cloud
100%
341
Can advection fog form over land
Yes - if lower atmosphere is stable
342
On weather map, diff in height for diff pressure level is called
Isohypes
343
A weather phenomenon that occurs predominantly around the coastline caused by unequal heating or cooling during day and night is called
Land Breeze which will occur during the day, because of rapid cooling of the land and the sea cool slower
344
What is mistral
Strong valley winds
345
Evaporation over a lake is greatest with
Strong & dry wind
346
Where is polar jet found
300hPa and bending is common
347
At the same alt, a parcel of air at 30degC compared to 10degC, which can hold ____ water vapour
More
348
NS gives
Steady moderate to heavy rain
349
RH is
Amount of water vapour the air can hold at its current temp
350
Ice forms on
Leading edge of tailplanes/aerials
351
Moist air less dense than dry air. True or false
True. Because water has a lower molecular weight than dry air. Therefore if you add water into dry air, it will reduce its mass and becomes less dense...
352
A parcel of saturated air is rising adiabatically
It will cool at 1.5deg per 1000ft
353
What is saturated vapour pressure
Partial pressure of water vapour
354
What best illustrate convection
A bubble of warm air by large scale burning, rises forming cloud
