Lesson 6

Clouds, fog, or dew will always form when A water vapor condenses. B water vapor is present. C relative humidity reaches 100 percent.

A

Moist, stable air flowing upslope can be expected to A produce stratus type clouds. B cause showers and thunderstorms. C develop convective turbulence.

A

One of the most easily recognized discontinuities across a front is A a change in temperature. B an increase in cloud coverage. C an increase in relative humidity.

A

One weather phenomenon which will always occur when flying across a front is a change in the A wind direction. B type of precipitation. C stability of the air mass.

A

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 down a mountain valley, and the air is unstable. C parallel to a mountain peak, and the air is stable.

A

The most frequent type of ground or surface-based temperature inversion is that which is produced by A terrestrial radiation on a clear, relatively still night. B warm air being lifted rapidly aloft in the vicinity of mountainous terrain. C the movement of colder air under warm air, or the movement of warm air over cold air.

A

Thunderstorms reach their greatest intensity during the A mature stage. B downdraft stage. C cumulus stage.

A

Thunderstorms which generally produce the most intense hazard to aircraft are A squall line thunderstorms. B steady-state thunderstorms. C warm front thunderstorms.

A

What are characteristics of a moist, unstable air mass? A Cumuliform clouds and showery precipitation. B Poor visibility and smooth air. C Stratiform clouds and showery precipitation.

A

What are characteristics of unstable air? A Turbulence and good surface visibility. B Turbulence and poor surface visibility. C Nimbostratus clouds and good surface visibility.

A

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

What are the standard temperature and pressure values for sea level? A 15 °C and 29.92 inches Hg. B 59 °C and 1013.2 millibars. C 59 °F and 29.92 millibars.

A

What causes variations in altimeter settings between weather reporting points? A Unequal heating of the Earth B Variation of terrain elevation. C Coriolis force.

A

What conditions are necessary for the formation of thunderstorms? A High humidity, lifting force, and unstable conditions. B High humidity, high temperature, and cumulus clouds. C Lifting force, moist air, and extensive cloud cover.

A

What feature is associated with a temperature inversion? A A stable layer of air. B An unstable layer of air. C Chinook winds on mountain slopes.

A

What is a characteristic of stable air? A Stratiform clouds. B Unlimited visibility. C Cumulus clouds.

A

What situation is most conducive to the formation of radiation fog? A Warm, moist air over low, flatland areas on clear, calm nights. B Moist, tropical air moving over cold, offshore water. C The movement of cold air over much warmer water.

A

What would decrease the stability of an air mass? A Warming from below. B Cooling from below. C Decrease in water vapor.

A

Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high? A Smooth air, poor visibility, fog, haze, or low clouds. B Light wind shear, poor visibility, haze, and light rain. C Turbulent air, poor visibility, fog, low stratus type clouds, and showery precipitation.

A

Which weather phenomenon is always associated with a thunderstorm? A Lightning. B Heavy rain. C Hail.

A

A nonfrontal, narrow band of active thunderstorms that often develop ahead of a cold front is a known as a A prefrontal system. B squall line. C dry line.

B

A stronger pressure gradient at higher altitudes. B friction between the wind and the surface. C stronger Coriolis force at the surface.

B

Clouds are divided into four families according to their A outward shape. B height range. C composition.

B

Crests of standing mountain waves may be marked by stationary, lens-shaped clouds known as A mammatocumulus clouds. B standing lenticular clouds. C roll clouds.

B

During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts? A Cumulus. B Dissipating. C Mature.

B

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 Precipitation static. B Wind-shear turbulence. C Steady rain.

B

In which situation is advection fog most likely to form? A A warm, moist air mass on the windward side of mountains. B An air mass moving inland from the coast in winter. C A light breeze blowing colder air out to sea.

B

The amount of water vapor which air can hold depends on the A dewpoint. B air temperature. C stability of the air.

B

The conditions necessary for the formation of cumulonimbus clouds are a lifting action and A unstable air containing an excess of condensation nuclei. B unstable, moist air. C either stable or unstable air.

B

The suffix 'nimbus,' used in naming clouds, means A a cloud with extensive vertical development. B a rain cloud. C a middle cloud containing ice pellets.

B

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

What clouds have the greatest turbulence? A Towering cumulus. B Cumulonimbus. C Nimbostratus.

B

What feature is normally associated with the cumulus stage of a thunderstorm? A Roll cloud. B Continuous updraft. C Frequent lightning.

B

What measurement can be used to determine the stability of the atmosphere? A Atmospheric pressure. B Actual lapse rate. C Surface temperature.

B

When may hazardous wind shear be expected? A 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. C Following frontal passage when stratocumulus clouds form indicating mechanical mixing.

B

Which conditions result in the formation of frost? A The temperature of the collecting surface is at or below freezing when small droplets of moisture fall on the surface. B 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 surrounding air is at or below freezing when small drops of moisture fall on the collecting surface.

B

Which weather phenomenon signals the beginning of the mature stage of a thunderstorm? A The appearance of an anvil top. B Precipitation beginning to fall. C Maximum growth rate of the clouds.

B

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

A stable air mass is most likely to have which characteristic? A Showery precipitation. B Turbulent air. C Smooth air.

C

A temperature inversion would most likely result in which weather condition? A Clouds with extensive vertical development above an inversion aloft. B Good visibility in the lower levels of the atmosphere and poor visibility above an inversion aloft. C An increase in temperature as altitude is increased.

C

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

Convective circulation patterns associated with sea breezes are caused by A warm, dense air moving inland from over the water. B water absorbing and radiating heat faster than the land. C cool, dense air moving inland from over the water.

C

Every physical process of weather is accompanied by, or is the result of, a A movement of air. B pressure differential. C heat exchange.

C

If an unstable air mass is forced upward, what type clouds can be expected? A Stratus clouds with little vertical development. B Stratus clouds with considerable associated turbulence. C Clouds with considerable vertical development and associated turbulence.

C

If the temperature/dewpoint spread is small and decreasing, and the temperature is 62 °F, what type weather is most likely to develop? A Freezing precipitation. B Thunderstorms. C Fog or low clouds.

C

In which environment is aircraft structural ice most likely to have the highest accumulation rate? A Cumulus clouds with below freezing temperatures. B Freezing drizzle. C Freezing rain.

C

Low-level turbulence can occur and icing can become hazardous in which type of fog? A Rain-induced fog. B Upslope fog. C Steam fog.

C

One in-flight condition necessary for structural icing to form is A small temperature/dewpoint spread. B stratiform clouds. C visible moisture.

C

Steady precipitation preceding a front is an indication of A stratiform clouds with moderate turbulence. B cumuliform clouds with little or no turbulence. C stratiform clouds with little or no turbulence.

C

The boundary between two different air masses is referred to as a A frontolysis. B frontogenesis. C front.

C

The development of thermals depends upon A a counterclockwise circulation of air. B temperature inversions. C solar heating.

C

The presence of ice pellets at the surface is evidence that there A are thunderstorms in the area. B has been cold frontal passage. C is a temperature inversion with freezing rain at a higher altitude.

C

Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain? A Constant altitude and airspeed. B Constant angle of attack. C Level flight attitude.

C

What cloud types would indicate convective turbulence? A Cirrus clouds. B Nimbostratus clouds. C Towering cumulus clouds.

C

What is meant by the term 'dewpoint'? A The temperature at which condensation and evaporation are equal. B The temperature at which dew will always form. C The temperature to which air must be cooled to become saturated.

C

What is the approximate base of the cumulus clouds if the surface air temperature at 1,000 feet MSL is 70 °F and the dewpoint is 48 °F? A 4,000 feet MSL. B 5,000 feet MSL. C 6,000 feet MSL.

C

What types of fog depend upon wind in order to exist? A Radiation fog and ice fog. B Steam fog and ground fog. C Advection fog and upslope fog.

C

Where does wind shear occur? A Only at higher altitudes. B Only at lower altitudes. C At all altitudes, in all directions.

C