Chapter 9 - Aviation Weather

What feature is associated with a temperature inversion?

A stable layer of air.
An unstable layer of air.
Chinook winds on mountain slopes.
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Terms in this set (63)
What feature is associated with a temperature inversion?

A stable layer of air.
An unstable layer of air.
Chinook winds on mountain slopes.
A stable layer of air.
What types of fog depend upon wind in order to exist?

Radiation fog and ice fog.
Steam fog and ground fog.
Advection fog and upslope fog.
Advection fog and upslope fog.
SIGMETs are issued as a warning of weather conditions hazardous to which aircraft?

Small aircraft only.
Large aircraft only.
All aircraft.
All aircraft.
The suffix 'nimbus,' used in naming clouds, means

a cloud with extensive vertical development.
a rain cloud.
a middle cloud containing ice pellets.
a rain cloud.
If the temperature/dewpoint spread is small and decreasing, and the temperature is 62°F, what type weather is most likely to develop?

Freezing precipitation.
Thunderstorms.
Fog or low clouds.
Fog or low clouds.
Low-level turbulence can occur and icing can become hazardous in which type of fog?

Rain-induced fog.
Upslope fog.
Steam fog.
Steam fog.
To get a complete weather briefing for the planned flight, the pilot should request

a general briefing.
an abbreviated briefing.
a standard briefing.
a standard briefing.
(UA/OV KOKC-KTUL/TM 1800/FL 120/TP BE90//SK BKN018-TOP055/OVC072-
TOP089/CLR ABV/TA M7/WV 08021/TB LGT 055-072/IC LGT-MOD RIME 072-089)
The intensity of the turbulence reported at a specific altitude is

moderate from 5,500 feet to 7,200 feet.
moderate at 5,500 feet and at 7,200 feet.
light from 5,500 feet to 7,200 feet.
light from 5,500 feet to 7,200 feet.
How does frost affect the lifting surfaces of an airplane on takeoff?

Frost may prevent the airplane from becoming airborne at normal takeoff speed.
Frost will change the camber of the wing, increasing lift during takeoff.
Frost may cause the airplane to become airborne with a lower angle of attack at a lower indicated airspeed.
Frost may prevent the airplane from becoming airborne at normal takeoff speed.
What is meant by the term 'dewpoint'?

The temperature at which condensation and evaporation are equal.
The temperature at which dew will always form.
The temperature to which air must be cooled to become saturated.
The temperature to which air must be cooled to become saturated.
(UA/OV KOKC-KTUL/TM 1800/FL 120/TP BE90//SK BKN018-TOP055/OVC072- TOP089/CLR ABV/TA M7/WV 08021/TB LGT 055-072/IC LGT-MOD RIME 072-089) The wind and temperature at 12,000 feet MSL as reported by a pilot are 090° at 21 MPH and -9 °F. 090° at 21 knots and -9 °C. 080° at 21 knots and -7°C.080° at 21 knots and -7°C.(UA/OV KOKC-KTUL/TM 1800/FL 120/TP BE90//SK BKN018-TOP055/OVC072- TOP089/CLR ABV/TA M7/WV 08021/TB LGT 055-072/IC LGT-MOD RIME 072-089) The base and tops of the overcast layer reported by a pilot are 1,800 feet MSL and 5,500 feet MSL. 5,500 feet AGL and 7,200 feet MSL. 7,200 feet MSL and 8,900 feet MSL.7,200 feet MSL and 8,900 feet MSL.(UA/OV KOKC-KTUL/TM 1800/FL 120/TP BE90//SK BKN018-TOP055/OVC072- TOP089/CLR ABV/TA M7/WV 08021/TB LGT 055-072/IC LGT-MOD RIME 072-089) The intensity and type of icing reported by a pilot is light to moderate. light to moderate rime. light to moderate clear.light to moderate rime.Which type weather briefing should a pilot request, when departing within the hour, if no preliminary weather information has been received? Outlook briefing. Abbreviated briefing. Standard briefing.Standard briefing.What are the current conditions depicted for Chicago Midway Airport (KMDW)? SPECI KMDW 121856Z 32005KT 1 1/2 SM RA OVC007 17/16 A2980 RMK RAB35 Sky 700 feet overcast, visibility 1-1/2 SM, rain. Sky 7000 feet overcast, visibility 1-1/2 SM, heavy rain. Sky 700 feet overcast, visibility 11, occasionally 2 SM, with rain.Sky 700 feet overcast, visibility 1-1/2 SM, rain.When speaking to a flight service weather briefer, you should state the pilot-in-command's full name and address. a summary of your qualifications. whether the flight is VFR or IFR.whether the flight is VFR or IFR.Every physical process of weather is accompanied by, or is the result of, a movement of air. pressure differential. heat exchange.heat exchange.How will frost on the wings of an airplane affect takeoff performance? Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability. Frost will change the camber of the wing, increasing its lifting capability. Frost will cause the airplane to become airborne with a higher angle of attack, decreasing the stall speed.Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability.Clouds are divided into four families according to their outward shape. height range. compositionheight range.Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain? Constant altitude and airspeed. Constant angle of attack. Level flight attitude.Level flight attitude.An almond or lens-shaped cloud which appears stationary, but which may contain winds of 50 knots or more, is referred to as an inactive frontal cloud. a funnel cloud. a lenticular cloud.a lenticular cloud.Which weather phenomenon signals the beginning of the mature stage of a thunderstorm? The appearance of an anvil top. Precipitation beginning to fall. Maximum growth rate of the clouds.Precipitation beginning to fall.A weather briefing that is provided when the information requested is 6 or more hours in advance of the proposed departure time is an outlook briefing. a forecast briefing. a prognostic briefing.an outlook briefing.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? Precipitation static. Wind-shear turbulence. Steady rain.Wind-shear turbulence.Which conditions result in the formation of frost? The temperature of the collecting surface is at or below freezing when small droplets of moisture fall on the surface. The temperature of the collecting surface is at or below the dewpoint of the adjacent air and the dewpoint is below freezing. The temperature of the surrounding air is at or below freezing when small drops of moisture fall on the collecting surface.The temperature of the collecting surface is at or below freezing when small droplets of moisture fall on the surface.What are characteristics of a moist, unstable air mass? Cumuliform clouds and showery precipitation. Poor visibility and smooth air. Stratiform clouds and showery precipitation.Cumuliform clouds and showery precipitation.Which in-flight advisory would contain information on severe icing not associated with thunderstorms? Convective SIGMET. SIGMET. AIRMET.SIGMET.Steady precipitation preceding a front is an indication of stratiform clouds with moderate turbulence. cumuliform clouds with little or no turbulence. stratiform clouds with little or no turbulence.stratiform clouds with little or no turbulence.The conditions necessary for the formation of cumulonimbus clouds are a lifting action and unstable air containing an excess of condensation nuclei. unstable, moist air. either stable or unstable air.unstable, moist air.The wind at 5,000 feet AGL is southwesterly while the surface wind is southerly. This difference in direction is primarily due to stronger pressure gradient at higher altitudes. friction between the wind and the surface. stronger Coriolis force at the surface.friction between the wind and the surface.Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow across a mountain ridge, and the air is stable. down a mountain valley, and the air is unstable. parallel to a mountain peak, and the air is stable.across a mountain ridge, and the air is stable.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? 9,000 feet AGL. 10,000 feet AGL. 11,000 feet AGL.10,000 feet AGL. When lifted, unsaturated air cools at approximately 5.4°F per 1,000 feet. The dew point cools at approximately 1°F per 1,000 feet. Therefore, the convergence of the temperature and dew point lapse rates is 4.4°F per 1,000 feet. The base of a cloud (AGL) that is formed by vertical currents can be roughly calculated by dividing the difference between the surface temperature and the dew point by 4.4 and multiplying the rounded result by1,000. 1. 82°F surface temperature - 38°F dew point = 44°F 2. 44 ÷ 4.4 = 10 3. 10 x 1,000 = 10,000 feet AGLTo best determine general forecast weather conditions covering a flight information region, the pilot should refer to Graphical Forecasts for Aviation (GFA). Weather Depiction Charts. Satellite Maps.Graphical Forecasts for Aviation (GFA).(UA/OV KOKC-KTUL/TM 1800/FL 120/TP BE90//SK BKN018-TOP055/OVC072- TOP089/CLR ABV/TA M7/WV 08021/TB LGT 055-072/IC LGT-MOD RIME 072-089) If the terrain elevation is 1,295 feet MSL, what is the height above ground level of the base of the ceiling? 505 feet AGL. 1,295 feet AGL. 6,586 feet AGL.505 feet AGL.When there is a temperature inversion, you would expect to experience clouds with extensive vertical development above an inversion aloft. good visibility in the lower levels of the atmosphere and poor visibility above an inversion aloft. an increase in temperature as altitude increases.an increase in temperature as altitude increases.What feature is normally associated with the cumulus stage of a thunderstorm? Roll cloud. Continuous updraft. Frequent lightning.Continuous updraft.The amount of water vapor which air can hold depends on the dewpoint air temperature. stability of the air.air temperature.If an unstable air mass is forced upward, what type clouds can be expected? Stratus clouds with little vertical development. Stratus clouds with considerable associated turbulence. Clouds with considerable vertical development and associated turbulence.Clouds with considerable vertical development and associated turbulence.Clouds, fog, or dew will always form when water vapor condenses. water vapor is present. relative humidity reaches 100 percent.water vapor condenses.What causes variations in altimeter settings between weather reporting points? Unequal heating of the Earth's surface. Variation of terrain elevation. Coriolis force.Unequal heating of the Earth's surface.Thunderstorms which generally produce the most intense hazard to aircraft are squall line thunderstorms. steady-state thunderstorms. warm front thunderstorms.squall line thunderstorms.What is a characteristic of stable air? Stratiform clouds. Unlimited visibility. Cumulus clouds.Stratiform clouds.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. warm air being lifted rapidly aloft in the vicinity of mountainous terrain. the movement of colder air under warm air, or the movement of warm air over cold air.terrestrial radiation on a clear, relatively still night.The remarks section for KMDW has RAB35 listed. This entry means blowing mist has reduced the visibility to 1-1/2 SM. rain began at 1835Z. the barometer has risen .35" Hg.rain began at 1835Z.One of the most easily recognized discontinuities across a front is a change in temperature. an increase in cloud coverage. an increase in relative humidity.a change in temperature.What would decrease the stability of an air mass? Warming from below. Cooling from below. Decrease in water vapor.Warming from below.What should pilots state initially when telephoning a weather briefing facility for preflight weather information? The intended route of flight radio frequencies. The address of the pilot in command. The intended route of flight and destination.The intended route of flight and destination.One in-flight condition necessary for structural icing to form is small temperature/dewpoint spread. stratiform clouds. visible moisture.visible moisture.Where does wind shear occur? Only at higher altitudes. Only at lower altitudes. At all altitudes, in all directions.At all altitudes, in all directions.AIRMET's are advisories of significant weather phenomena but of lower intensities than SIGMET's and are intended for dissemination to only IFR pilots. all pilots. only VFR pilots.all pilots.When telephoning a weather briefing facility for preflight weather information, pilots should state whether they intend to fly VFR only. that they possess a current pilot certificate. the full name and address of the formation commander.whether they intend to fly VFR only.What information is contained in a CONVECTIVE SIGMET? Tornadoes, embedded thunderstorms, and hail 3/4 inch or greater in diameter. Severe icing, severe turbulence, or widespread dust storms lowering visibility to less than 3 miles. Surface winds greater than 40 knots or thunderstorms equal to or greater than video integrator processor (VIP) level 4.Tornadoes, embedded thunderstorms, and hail 3/4 inch or greater in diameter.What cloud types would indicate convective turbulence? Cirrus clouds. Nimbostratus clouds. Towering cumulus clouds.Towering cumulus clouds.To update a previous weather briefing, a pilot should request an abbreviated briefing. a standard briefing. an outlook briefing.an abbreviated briefing.What values are used for Winds Aloft Forecasts? Magnetic direction and knots. Magnetic direction and miles per hour. True direction and knots.True direction and knots.What situation is most conducive to the formation of radiation fog? Warm, moist air over low, flatland areas on clear, calm nights. Moist, tropical air moving over cold, offshore water. The movement of cold air over much warmer water.Warm, moist air over low, flatland areas on clear, calm nights.The presence of ice pellets at the surface is evidence that there are thunderstorms in the area. has been cold frontal passage. is a temperature inversion with freezing rain at a higher altitude.is a temperature inversion with freezing rain at a higher altitude.When requesting weather information for the following morning, a pilot should request an outlook briefing. a standard briefing. an abbreviated briefing.an outlook briefing.What are the processes by which moisture is added to unsaturated air? Evaporation and sublimation. Heating and condensation. Supersaturation and evaporation.Evaporation and sublimation.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 10 knots. 15 knots. 25 knots.25 knots.Thunderstorms reach their greatest intensity during the mature stage. downdraft stage. cumulus stage.mature stage.When may hazardous wind shear be expected? When stable air crosses a mountain barrier where it tends to flow in layers forming lenticular clouds. In areas of low-level temperature inversion, frontal zones, and clear air turbulence. Following frontal passage when stratocumulus clouds form indicating mechanical mixing.In areas of low-level temperature inversion, frontal zones, and clear air turbulence.When the term 'light and variable' is used in reference to a Winds Aloft Forecast, the coded group and windspeed is 0000 and less than 7 knots. 9900 and less than 5 knots. 9999 and less than 10 knots.9900 and less than 5 knots.