weather Flashcards
The wind at 5,000 feet AGL is southwesterly while the surface wind is southerly. This difference in direction is primarily due to:
A.stronger pressure gradient at higher altitudes
B.friction between the wind and the surface
C.stronger Coriolis force at the surface
B.friction between the wind and the surface
The conditions necessary for the formation of cumulonimbus clouds are a lifting action and
A.either stable or unstable air
B.unstable, moist air
C.unstable air containing an excess of condensation nuclei
B.unstable, moist air
The mature stage of a thunderstorm begins with
A.continuous downdrafts
B.the start of precipitation
C.formation of the anvil top
B.the start of precipitation
Convective circulation patterns associated with sea breezes are caused by
A.water absorbing and radiating heat faster than the land
B.warm, dense air moving inland from over the water
C.cool, dense air moving inland from over the water
C.cool, dense air moving inland from over the water
Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?
A.Light wind shear, poor visibility, haze, and light rain
B.Smooth air, poor visibility, fog, haze, or low clouds
C.Turbulent air, poor visibility, fog, low stratus type clouds, and showery precipitation
B.Smooth air, poor visibility, fog, haze, or low clouds
In which environment is aircraft structural ice most likely to have the highest accumulation rate?
A.Freezing drizzle
B.Cumulus clouds with below freezing temperatures
C.Freezing rain
C.Freezing rain
Which weather phenomenon is always associated with a thunderstorm?
A.Heavy rain
B.Hail
C.Lightning
C.Lightning
What would decrease the stability of an air mass?
A.Cooling from below
B.Warming from below
C.Decrease in water vapor
B.Warming from below
The suffix “nimbus,” used in naming clouds, means
A.a cloud with extensive vertical development
B.a middle cloud containing ice pellets
C.a rain cloud
C.a rain cloud
When may hazardous wind shear be expected?
A.Following frontal passage when stratocumulus clouds form indicating mechanical mixing
B.In areas of low-level temperature inversion, frontal zones, and clear air turbulence
C.When stable air crosses a mountain barrier where it tends to flow in layers forming lenticular clouds
B.In areas of low-level temperature inversion, frontal zones, and clear air turbulence
If an unstable air mass is forced upward, what type clouds can be expected?
A.Clouds with considerable vertical development and associated turbulence
B.Stratus clouds with considerable associated turbulence
C.Stratus clouds with little vertical development
A.Clouds with considerable vertical development and associated turbulence
One of the most easily recognized discontinuities across a front is
A.a change in temperature
B.an increase in relative humidity
C.an increase in cloud coverage
A.a change in temperature
Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow
A.across a mountain ridge, and the air is stable
B.parallel to a mountain peak, and the air is stable
C.down a mountain valley, and the air is unstable
A.across a mountain ridge, and the air is stable
What causes variations in altimeter settings between weather reporting points?
A.Unequal heating of the Earth’s surface
B.Variation of terrain elevation
C.Coriolis force
A.Unequal heating of the Earth’s surface
The boundary between two different air masses is referred to as a
A.front
B.frontolysis
C.frontogenesis
A.front
When warm, moist, stable air flows upslope, it
A.produces stratus type clouds
B.causes showers and thunderstorms
C.develops convective turbulence
A.produces stratus type clouds
If there is thunderstorm activity in the vicinity of an airport at which you plan to land, which hazardous atmospheric phenomenon might be expected on the landing approach?
A.Wind-shear turbulence
B.Steady rain
C.Precipitation static
A.Wind-shear turbulence
A nonfrontal, narrow band of active thunderstorms that often develop ahead of a cold front is known as a
A.dry line
B.squall line
C.prefrontal system
B.squall line
The stability of an air mass can usually be determined by
A.cloud types and the type of precipitation
B.measuring the dry adiabatic lapse rate
C.the height of the tropopause
cloud types and the type of precipitation
What is meant by the term “dewpoint”?
A.The temperature at which dew will always form
B.The temperature to which air must be cooled to become saturated
C.The temperature at which condensation and evaporation are equal
B.The temperature to which air must be cooled to become saturated
Which conditions result in the formation of frost?
A.The temperature of the surrounding air is at or below freezing when small drops of moisture fall on the collecting surface
B.The temperature of the collecting surface is at or below freezing when small droplets of moisture fall on the surface
C.The temperature of the collecting surface is at or below the dewpoint of the adjacent air and the dewpoint is below freezing
C.The temperature of the collecting surface is at or below the dewpoint of the adjacent air and the dewpoint is below freezing
Low-level turbulence can occur and icing can become hazardous in which type of fog?
A.Steam fog
B.Upslope fog
C.Rain-induced fog
A.Steam fog
What conditions are necessary for the formation of thunderstorms?
A.High humidity, high temperature, and cumulus clouds
B.High humidity, lifting force, and unstable conditions
C.Lifting force, moist air, and extensive cloud cover
B.High humidity, lifting force, and unstable conditions
In which situation is advection fog most likely to form?
A.An air mass moving inland from the coast in winter
B.A light breeze blowing colder air out to sea
C.A warm, moist air mass on the windward side of mountains
air mass moving inland from the coast in winter
Cumulus clouds often indicate
A.a temperature inversion
B.possible turbulence
C.a dry adiabatic lapse rate
B.possible turbulence
What are the processes by which moisture is added to unsaturated air?
A.Evaporation and sublimation
B.Heating and condensation
C.Supersaturation and evaporation
A.Evaporation and sublimation
Clouds are divided into four families according to their
A.height range
B.composition
C.outward shape
A.height range
If the temperature/dewpoint spread is small and decreasing, and the temperature is 62°F, what type weather is most likely to develop?
A.Thunderstorms
B.Fog or low clouds
C.Freezing precipitation
B.Fog or low clouds
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?
A.Precipitation beginning to fall
B.The appearance of an anvil top
C.Maximum growth rate of the clouds
A.Precipitation beginning to fall
The amount of water vapor which air can hold depends on the
A.air temperature
B.stability of the air
C.dewpoint
A.air temperature
What are characteristics of a moist, unstable air mass?
A.Stratiform clouds and showery precipitation
B.Cumuliform clouds and showery precipitation
C.Poor visibility and smooth air
B.Cumuliform clouds and showery precipitation
During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?
A.Cumulus
B.Mature
C.Dissipating
C.Dissipating
What cloud types would indicate convective turbulence?
A.Cirrus clouds
B.Towering cumulus clouds
C.Nimbostratus clouds
B.Towering cumulus clouds
What measurement can be used to determine the stability of the atmosphere?
A.Atmospheric pressure
B.Surface temperature
C.Actual lapse rate
C.Actual lapse rate
What feature is associated with a temperature inversion?
A.An unstable layer of air
B.A stable layer of air
C.Chinook winds on mountain slopes
B.A stable layer of air
One weather phenomenon which will always occur when flying across a front is a change in the
A.type of precipitation
B.wind direction
C.stability of the air mass
B.wind direction
A pilot can expect a wind-shear zone in a temperature inversion whenever the wind speed at 2,000 to 4,000 feet above the surface is at least
A.10 knots
B.15 knots
C.25 knots
C.25 knots
Clouds with extensive vertical development over mountainous terrain are a sign of
A.a stable air mass
B.an unstable air mass
C.a dry adiabatic lapse rate
B.an unstable air mass
The development of thermals depends upon
A.temperature inversions
B.solar heating
C.a counterclockwise circulation of air
B.solar heating
What feature is normally associated with the cumulus stage of a thunderstorm?
A.Roll cloud
B.Continuous updraft
C.Frequent lightning
B.Continuous updraft
At approximately what altitude above the surface would the pilot expect the base of cumuliform clouds if the surface air temperature is 82°F and the dewpoint is 38°F?
A.9,000 feet AGL
B.11,000 feet AGL
C.10,000 feet AGL
C.10,000 feet AGL
An almond or lens-shaped cloud which appears stationary, but which may contain winds of 50 knots or more, is referred to as
A.an inactive frontal cloud
B.a funnel cloud
C.a lenticular cloud
C.a lenticular cloud
One in-flight condition necessary for structural icing to form is
A.small temperature/dewpoint spread
B.visible moisture
C.stratiform clouds
B.visible moisture
What are the characteristics of an unstable atmosphere?
A.Descending air in the northern hemisphere
B.A cool, dry air mass
C.A warm, humid air mass
C.A warm, humid air mass