Private Pilot: Weather Theory

Every physical process of weather is accompanied by or is the result of...

Heat Exchange

What causes variations in altimeter settings between weather reporting points?

Unequal heating of the Earth's surface

The development of thermals depends on upon...

Solar heating

Convective circulation patterns associated with sea breezes are caused by...

Cooler air moving inland from over the water

A temperature inversion would most likely result in which weather condition?

An increase in temperature as altitude is increased

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

What is meant by the term dew-point?

The temperature to which air must be cooled in order to become saturated

The amount of water vapor which air can hold depends on the...

Air temperature

Clouds, fog, or dew will always form when

Water vapor is present

What are the processes by which moisture is added to unsaturated air?

Evaporation and sublimation

If the temperature/dew point spread is small and decreasing and the temperature is 62°F, what type of weather is most likely to develop?

Fog or low clouds

The boundary between two different air masses is referred to as a...

Front

One of the most easily recognized discontinuities across the front is...

A change in temperature

One weather phenomenon which will always occur with flying across a front is a change in the...

Wind direction

Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?

Smooth air

Poor visibility

Fog, haze, or low clouds

What measurement can be used to determine the stability of the atmosphere?

Actual lapse rate

What would decrease the stability of an air mass?

Warming from below

What is a characteristic of stable air?

Stratiform clouds

What feature is associated with a temperature inversion?

A stable layer of air

What are characteristics of a moist, unstable air mass?

Cumuliform clouds and showery precipitation

What are characteristics of unstable air?

Turbulence and good surface visibility

A stable air mass is most likely to have which characteristic?

Poor surface visibility

Moist, stable air flowing upslope can be expected to...

Produce stratus-type clouds

If an unstable air mass is forced upward, what type clouds can be expected?

Clouds with considerable vertical development and associated turbulence

Steady precipitation preceding a front is an indication of...

Stratiform clouds with little or no turbulence

The conditions necessary for the formation of cumulonimbus clouds are a lifting action and...

Unstable, moist air

What is the approximate base of the cumulus clouds if the surface air temperature at 1000 feet MSL, 70°F and the dew point is 48°?

6000' MSL

At approximately what altitude above the surface would a pilot expect the base of cumuliform clouds if the surface air temperature is 82°F and the dewpoint is 38°F?

10,000 feet AGL

The suffix" Nimbus" used in naming clouds means...

Rain-bearing

Clouds are divided into four families according to their...

Height range (Altitude)

What clouds have the greatest turbulence?

Cumulonimbus

An almond or lens-shaped cloud which appears stationary but which may contain winds of 15 kts or greater is referred to as...

A lenticular cloud

Crests of standing mountain waves may be marked by stationary lens-shaped clouds known as...

Standing lenticular clouds

What cloud types would indicate convective turbulence?

Towering cumulus

Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow...

Across a mountain ridge and the air is stable

Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain?

Level flight attitude

What feature is normally associated with the cumulus stage of a thunderstorm?

Continuous updraft

Which weather phenomenon signals the beginning of the mature stage of with thunderstorm?

Precipitation beginning to fall

What conditions are necessary for the formation of thunderstorms?

High humidity

Lifting force

Unstable atmosphere

During the lifecycle of a thunderstorm which stage is characterized predominantly by downdrafts?

Dissipating

Thunderstorms reach their greatest intensity during the__________________stage

Mature

Thunderstorms which generally produce the most intense hazard to aircraft are...

Squall line thunderstorms

A non-frontal narrow band of active thunderstorms that often develop ahead of a cold front is known as a...

Squall line

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?

Wind shear turbulence

Which weather phenomenon is always associated with a thunderstorm?

Lightning

Your destination airport has one runway 08 - 26 and the wind is calm. The normal approach with calm wind is a left-hand pattern to runways 08. There is no other traffic at the airport. A thunderstorm about 6 miles west is beginning its mature stage, and rain is starting to reach the ground. The pilot decides to...

Fly and approach to runway 26, since any unexpected winds due to the storm will be westerly

Where does windshear occur?

At all altitudes in all directions

When may hazardous windshear be expected?

In areas of low-level temperature inversion, frontal zones, and clear-air turbulence

A pilot can expect a winds shear zone in a temperature inversion whenever the wind speed at 2000 to 4000 feet ASL is at least...

25 knots

The presence of ice pellets at the surface is evidence that there is...

A temperature inversion with freezing rain at a higher altitude

One in-flight condition necessary for structural icing to form is...

Visible moisture

In which environment is aircraft structural ice most likely to have the highest accumulation rate?

Freezing rain

During an IFR cross-country flight you picked up rime icing which you estimate is ½" thick on the leading edge of the wings. You are now below the clouds at 2000 feet AGL and are approaching your destination airport under VFR visibility. Winds at the destination airport are 8 knots right down the runway and the surface temperature is 3°C you decide to...

Use a faster than normal approach and landing speed

What situation is most conducive to the formation of radiation fog?

Warm, moist air over low, flat land areas on clear, calm nights

In which situation is advection fog most likely to form?

An air mass moving inland from the coast in winter

What types of fog depend upon wind in order to exist?

Advection fog and upslope fog

Low-level turbulence can occur, and icing can become hazardous in which type of fog?

Steam fog

Which conditions result in the formation of frost?

The temperature of the collecting surface is at or below the dewpoint of the and adjacent air and the dew point is below freezing

How does frost affect the lifting surfaces of an airplane on takeoff?

Frost may prevent airplane from becoming airborne at normal takeoff speed

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 lifting capability

Why is frost considered hazardous to flight operation?

Frost spoils the smooth flow of air over the wings thereby decreasing lifting capability

(Refer to Figure 12.)

Which of the reporting stations have VFR weather?

Kink KB0I and KLAX

For aviation purposes, ceiling is defined as the height above the Earth's surface of the...

Lowest broken or overcast layer or vertical visibility into an obscuration

(Refer to Figure 12).

The wind direction and velocity at KJFK is from...

180° true at 4 knots

(Refer to figure 12).

What are the wind conditions at wink Texas KINK

110° at 12 knots, gusts 18 knots

(Refer to figure 12).

The remarks section for KMDW has RAB35 listed at this entry means...

Rain began at 1835Z

(Refer to Figure 12).

What are the current conditions depicted for Chicago Midway Airport (KMDW)?

Sky 700 feet overcast, visibility 1-1/2 SM, rain

(Refer to figure 14).

The base and top of the overcast layer reported by a pilot are...

7200 feet MSL and 8900 feetMSL

(Refer to figure 14).

The wind and temperature at 12,000 feet MSL as reported by a pilot are...

80° at 21 knots and -7°C

(Refer to figure 14).

If the terrain elevation is 1295' MSL, what is the height above ground level of the base of the ceiling?

505' AGL

(Refer to Figure 14.)

The intensity of the turbulence reported at a specific altitude is...

Light from 5500' to 7200'

(Refer to Figure 14.)

The intensity and type of icing reported by a pilot is...

Light to moderate rime

(Refer to figure 15).

What is the valid period for the TAF for KMEM?

1800Z to 1800Z

(Refer to figure 15).

In the TAF for KMEM what does SHRA stand for?

Rain showers

(Refer to figure 15).

Between 1000Z and 1200Z the visibility at KMEM is forecast to be...

3 statute miles

(Refer to figure 15).

What is the forecast wind for KMEM from 1600Z until the end of the forecast?

Variable in direction at 6 knots

(Refer to figure 15).

In the TAF from KOKC the FM(from) group is forecast for the hours from 1600Z to 2200Z with the wind from...

180° at 10 knots.

(Refer to Figure 15.)

In the TAF from KOKC, the clear sky becomes...

Overcast at 2000 feet during the forecast period between 2200Z and 2400Z

(Refer to Figure 15).

During the time period from 0600 to 0800 what visibility is forecast for KOKC?

Greater than 6 statute miles

(Refer to Figure 15).

The only cloud type forecast in TAF reports is...

Cumulonimbus

From which primary source should information be obtained regarding expected weather at the estimated time of arrival if your destination has no Terminal Forecast?

Area Forecast

To best determine general forecast weather conditions covering a flight information region the pilot should refer to...

Aviation Area Forecasts.

(Refer to Figure 16).

What is the outlook for the southern half of Indiana after 0700Z?

VFR

To determine the freezing level and areas of probable icing aloft, the pilot should refer to the...

In-flight aviation weather advisories

The section of the Area Forecast entitled "VFR CLDS/WX" contains a general description of...

Clouds and weather which cover an area greater than 3000 square miles and a significant risk to VFR flight operations

(Refer to Figure 16).

What sky condition and visibility are forecast for upper Michigan in the eastern portions after 2300Z?

Ceiling 1000' overcast and 3-5 SM visibility

(Refer to Figure 16).

The Chicago FA forecast section is valid until the 25th at what time?

0800Z

(Refer to Figure 16).

What sky condition and light obstructions to vision are forecast for upper Michigan and western portions of 0200Z until 0500Z?

Ceiling becoming 1000' overcast with visibility 3-5 SM and mist

(Refer to Figure 17).

What wind is forecast for STL and 9000'?

230° true at 32 kts

(Refer to Figure 17).

What wind is forecast for STL at 12,000'?

230° true at 39 kts

(Refer to Figure 17).

Determine the wind and temperature aloft forecast for DEN at 9000'

230° true at 21 kts

Temperature -4°C

(Refer to Figure 17).

Determine the wind and temperature aloft forecast for MKC at 6000'

200° true at 6 kts

Temperature +3°C

(Refer to Figure 17).

What wind is forecast for STL at 12,000'?

230° true at 39 kts

What values are used for winds aloft forecasts?

True direction and knots

When the term" light and variable" is used in reference to winds aloft forecast and coded groups, the wind speed is denoted as__________, and is less than __________kts

9900, 5

(Refer to Figure 18).

What is the status of the front that expands from Nebraska to the upper Peninsula of Michigan?

Cold

(Refer to Figure 18).

IFR weather in northern Texas is due to...

Low ceilings

(Refer to Figure 18).

What value is the weather depicted chart to the pilot?

Determining general weather conditions on which to base flight planning

(Refer to Figure 18).

The marginal weather in central Kentucky is due to low______________

Ceiling

(Refer to Figure 18).

What weather phenomenon is causing IFR conditions in central Oklahoma?

Low ceilings and low visibility