61 terms

ASA FAA written

Weather phenomenon is always associated with a thunder storm
Lightning-cumulonimbus cloud
Temperaturre inversions result in which weather conditions?
An increase in Temperature as altitude is increased.
What feature is normally associated with the cumulus stage of a TS
Continuous updrafts.
Characteristic of stable air
Stratiform clouds
One in flight condition necessary for structural icing to form is
visible moisture
Moist, stable air flowing upslope can be expected to
produce stratus type clouds
What are characteristics of a moist, unstable air mass?
Cumuliform clouds and showery precipitation.
Upon encountering sever turbulence, which flight condition should the pilot attempt to maintain
Level flight altitude
Suffix "nimbus," used in naming clouds, means
a rain cloud
Stable air
Turb and good surface vis.
What is the approximate base of the cumulus clouds if the surface air temperature at 1,000 feet MSL is 70 F and the dew point spread is 48F?
6000 feet MSL
Exp. When lifted, unsaturated air cools at approximately 5.4 F per 1,000 feet. The dew point cools at approximately 1F per 1000feet. Therefore, the convergence of the temperature and dew point lapse rates is 4.4F per 1000feet. The base of the cloud that is formed by vertical currents can be can be calculated by dividing the difference between the surface temp and the dew point by 4.4 and mult the rounded result by 1,000.
Formula base of cumulus clouds
Surface temperature -dew point=22F
22 divided by 4.4=5
5 X 1,000=5000 AGL
5000 feet AGL + 1000 feet field elevation=6000
The wind at 5000 feet AGL is southwesterly while the surface wind is southerly. This difference in direction is primarily due to
Friction between the wind and the surface
The most frequent type of ground or surface based temperature inversion is that which is produced by
terrestrial radiation on a clear, relatively still night.
Presence of ice pellets at the surface is evidence that there
is a temperature inversion with freezing rain at a higher altitude
The amount of water vapor which air can hold depends on the
air temperature
Clouds, fog, or dew will always form when
water vapor condenses
Convective circulation patterns associated with sea breezes are caused by
Cool, dense air moving inland from over the water.
Structural ice accumulation most likely to build up
Freezing rain
A pilot can expect a wind shear zone in a temperature inversion whenever the windspeed at 2,000 to 4,000 feet above the surface is at least
25 knotts
If the Temperature/dew point spread is small and decreasing, and the temperature is 62F, what type weather is most likely to develop?
Fog or low clouds.
TS reach greatest intensity at
mature stage
If there is TS activity in the vicinity of an airport at which you plan to land, which hazardous atmospheric phenomenon might be expected on the landing approach?
Wind-shear turbulence
Results in formation of frost
The temperature of the collecting surface is at or below the dew point of the adjacent air and the dew point is below freezing
Where does wind shear occur?
at all altitudes, in all directions
One of the most easily recognized discontinuities across a front is
a change in temperature
During TS cycle, which stage is characterized predominantly by down drafts?
TS that generally produce the most intense hazards to aircraft are
squall line TS
Convective turbulence
Towering cumulus clouds
The boundary between two different air masses is referred to as a
A non frontal, narrow band of active TSs that often develop ahead of a cold front is known as a
Squall line
What is meant by the term "dew point"
the temperature to which air must be cooled to become saturated
Crests of standing mountain waves may be marked by stationary, lens-shaped clouds known as
standing lenticular clouds
Steady precipitation preceding a front is an indication of
stratiform clouds with little or no turbulence.
Associated with temperature inversion
a stable layer of air
What type of fog depend upon wind in order to exist?
advection fog and upslope fog.
If an unstable air mass is forced upward, what type clouds can be expected?
Clouds with considerable vertical development and associated turbulence.
What conditions are necessary for the formation of TS
High humidity, lifting force, and unstable conditions.
How does frost affect the lifting surfaces of an airplane on takeoff?
Frost may prevent the airplane from becoming airborne at normal takeoff speed.
Measurement that can be used to determine the stability of the atmosphere?
Actual lapse rate
At approximately what alt above surface would the pilot expect the base of a cumuliform clouds if the surface air temperature is 82F and the dew point is 38F?
1000 feet AGL
Frost on the wings will affect take off performance
disrupting the smooth flow of air over the wing, adversely affecting its lifting capability.
Frost is considered hazardous to flight because
Frost spoils the smooth flow of air over the wings, thereby decreasing lifting capability.
Conductive to the formation of radiation fog
Warm, moist air over low, flatland areas on clear, calm nights.
Low-level turbulence can occur and icing can become hazardous in which type of fog?
Steam fog
Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow
across a mountain ridge, and the air is stable.
Advection fog would most likely be able to form
An air mass moving inland from the coast in winter.
A stable air mass is most likely to have which characteristic?
Poor surface visibility.
Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?
Smooth air, poor vis, fog, haze, or low clouds.
What are the processes by which moisture is added to unsaturated air?
Evaporation and sublimation
What would decrease the stability of an air mass?
warming from below
Clouds are divided into four families according to their
height range
Every physical process of weather is accompanied by, or is the result of, a
heat change
Weather phenomenon signals the beginning of the mature stage of a TS
Precipitation beginning to fall
An almond or lens-shaped cloud wich appears stationary, but which may contain winds of 50 knots or more, is referred to as
lenticular cloud
One weather phenomenon which will always occur when flying across a front is a change in the
wind direction
Hazardous wind shear can be expected
in areas of low level temperature inversion, frontal zones, and clear air turbulence.
The conditions necessary for the formation of cumulonimbus clouds are a lifting action and
unstable, moist air.
What causes variations in altimeter settings between weather reporting points?
Unequal heating of the Earth's surface
Clouds have greatest Turbulence
Cumulonimbus clouds
Use faster approach and landing speed
ice on wings cold wind