Aviation Weather Flashcards
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.
Ceiling is defined as the height (AGL) of the lowest broken or overcast layer aloft or vertical visibility into an obscuration.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 3
(Refer to figure 15.) In the TAF from KOKC, the clear sky becomes
overcast at 2,000 feet during the forecast period between 2200Z and 2400Z.
SKC BECMG 0522/0524 20013G20KT 4SM SHRA OVC020 means that the clear sky will be becoming between 2200Z and 2400Z, winds from 200° at 13 knots, gusting to 20 knots, 4 statute miles visibility in rain showers with an overcast at 2000’.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
What are the standard temperature and pressure values for sea level?
15 °C and 29.92 inches Hg.
These are the standard temperature and pressure values. 59° F and 1013.2 millibars would also be correct.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
Aviation Weather (AC 00-6) Ch. 1
Every physical process of weather is accompanied by, or is the result of, a
heat exchange.
The amount of solar energy received by any region of the Earth varies. These differences create temperature variations, which create forces that drive the atmosphere in its endless motions. Unequal heating of the Earth’s surface causes weather phenomena.
Aviation Weather (AC 00-6) Ch. 2
What clouds have the greatest turbulence?
Cumulonimbus.
Cumulonimbus are the ultimate manifestation of instability. Nearly the entire spectrum of flying hazards are contained in these clouds including violent turbulence.
Aviation Weather (AC 00-6) Ch. 13
(Refer to figure 15.) What is the valid period for the TAF for KMEM?
1800Z on the 12th to 2400Z on the 13th.
A TAF is generally valid for 24 or 30 hours. 1218/1324 indicates the forecast is for the 12th day of the month and is valid from 1800Z on the 12th until 2400Z on the 13th.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Absence of the sky condition and visibility on an ATIS broadcast indicates that
the ceiling is at least 5,000 feet and visibility is 5 miles or more.
The ceiling/sky condition, visibility, and obstructions to vision may be omitted from the ATIS broadcast if the ceiling is above 5,000’ and the visibility is more than 5 miles.
Aeronautical Information Manual (AIM) 4-1
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 knots.
A shear zone is likely above an inversion if the wind at 2,000 to 4,000’ is 25 knots or more.
Pilot Windshear Guide (AC 00-54)
During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?
Dissipating.
Downdrafts characterize the dissipating stage of a thunderstorm.
Aviation Weather (AC 00-6) Ch. 19
The zone between contrasting air masses is called a:
Front.
The boundary between two different air masses is called a front.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
When the term ‘light and variable’ is used in reference to a Winds Aloft Forecast, the coded group and windspeed is
9900 and less than 5 knots.
When the forecast speed is less than 5 knots, the coded group is “9900” and read, “LIGHT AND VARIABLE”.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 5
Aeronautical Information Manual (AIM) 7-1
SIGMETs are issued as a warning of weather conditions hazardous to which aircraft?
All aircraft.
A SIGMET advises of nonconvective weather that is potentially hazardous to all aircraft.
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aeronautical Information Manual (AIM) 7-1
What is indicated when a current CONVECTIVE SIGMET forecasts thunderstorms?
Thunderstorms obscured by massive cloud layers.
A Convective SIGMET contains data regarding severe thunderstorms, lines of thunderstorms, thunderstorms with wide spread heavy precipitation, and embedded thunderstorms. Embedded thunderstorms are those obscured by massive cloud layers.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
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?
10,000 feet AGL.
As a rule of thumb, divide the difference between the temperature and dew point by 4.4 to determine the height of the cloud base. 82° F - 38° F = 44. 44 / 4.4 = 10 (in thousands of feet) or 10,000’.
Aviation Weather (AC 00-6) Ch. 12
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 disrupts the smooth airflow over the wing and destroys lift. This may prevent the aircraft from taking off or it may require a significantly longer takeoff run to become airborne.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain?
Level flight attitude.
Maintain a constant attitude, let the aircraft “ride the waves”.
Pilot Windshear Guide (AC 00-54)
How can you determine the stability of an air mass?
Observe the cloud formations and type of precipitation.
Atmospheric stability is the property of the ambient air that either enhances or suppresses vertical motion of air parcels and determines which type of clouds and precipitation a pilot will encounter. Cumulus clouds indicate areas of instability in the atmosphere, and the air around and inside them is turbulent. Stratus clouds tend to form in layers and are indicative of a stable air mass.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
Aviation Weather (AC 00-6) Ch. 12
The layers of the atmosphere, beginning at the earth’s surface, are:
Troposphere, stratosphere, and mesosphere.
The vertical structure of the atmosphere is divided into layers, troposphere, stratosphere, and mesosphere.
AVIATION_WEATHER_HREF
A stable air mass is most likely to have which characteristic?
Poor surface visibility.
In stable air, flying is usually smooth. It can contain low ceilings and poor visibilities.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
The presence of cumulus clouds indicate:
Unstable air with clearer visibilities.
Cumulus clouds indicate unstable air and good visibility.
Aviation Weather (AC 00-6) Ch. 13
The Terminal Aerodrome Forecast (TAF) is:
Specific to an airport.
A TAF is a report established for the five statute mile radius around an airport.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
What information is contained in a CONVECTIVE SIGMET?
Tornadoes, embedded thunderstorms, and hail 3/4 inch or greater in diameter.
A Convective SIGMET contains data regarding severe thunderstorms including, tornadoes, and large hail, ¾” or more in diameter. Embedded thunderstorms are also forecast on Convective SIGMETs.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
What feature is normally associated with the cumulus stage of a thunderstorm?
Continuous updraft.
The key feature of the cumulus stage of a cumulonimbus is continuous updrafts.
Aviation Weather (AC 00-6) Ch. 19
What should pilots state initially when telephoning a weather briefing facility for preflight weather information?
The intended route of flight and destination.
The pilot should give clear and concise facts about his flight, which includes route of flight and destination.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 1
The mature stage of a thunderstorm begins with:
**the start of precipitation.** The mature stage of a thunderstorm is signaled by the formation of downdrafts which allows precipitation to fall. Aviation Weather (AC 00-6) Ch. 19
To update a previous weather briefing, a pilot should request
an abbreviated briefing.
An abbreviated briefing provides a supplement to disseminated data, an update to a previous briefing, or a briefing limited to specific information.
Aviation Weather Services (AC 00-45) Ch. 1
Aeronautical Information Manual (AIM) 7-1
(Refer to figure 18.) What is the status of the front that extends from Nebraska through the upper peninsula of Michigan?
Cold.
A cold front is symbolized as a line with pointed barbs pointing in the direction of movement.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 4
Steady precipitation preceding a front is an indication of
stratiform clouds with little or no turbulence.
Precipitation from stratiform clouds is usually steady and there is little or no turbulence.
Aviation Weather (AC 00-6) Ch. 10
What are characteristics of unstable air?
Turbulence and good surface visibility.
Unstable air is usually turbulent with good surface visibilities.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
(Refer to figure 15.) Between 1000Z and 1200Z the visibility at KMEM is forecast to be?
3 statute miles.
BECMG 1310/1312 00000KT 3SM means the weather will be becoming, between 1000Z and 1200Z, light and variable winds with a visibility of 3 statute miles.
Aviation Weather Services (AC 00-45) Ch. 5
The most accurate part of a forecast occurs:
At the beginning of the forecast period.
The most accurate part of a forecast is at the beginning of the forecast period since it is based on the most recent data.
Pilot’s Handbook of Aeronautical Knowledge Ch. 15
What is wake turbulence?
The counter rotating vortices off the wingtips of an airplane generating lift.
All aircraft generate wake turbulence during flight. This disturbance is caused by a pair of counter-rotating vortices trailing from the wingtips. The vortices from larger aircraft pose problems to encountering aircraft.
Pilot’s Handbook of Aeronautical Knowledge Ch. 14
You define an air mass as:
Large bodies of air with a uniform temperature and moisture.
An air mass is defined as an extensive body of air having fairly uniform properties of temperature and moisture.
Pilot’s Handbook of Aeronautical Knowledge
Layered clouds are called:
Stratus.
Stratus clouds are formed in layers—typical low clouds, like stratus, stratocumulus, and nimbostratus are layered.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
Which weather phenomenon is always associated with a thunderstorm?
Lightning.
A local storm, invariably produced by a cumulonimbus cloud, and always accompanied by lightning and thunder.
Aviation Weather (AC 00-6) Ch. 19
Crests of standing mountain waves may be marked by stationary, lens-shaped clouds known as
standing lenticular clouds.
Standing lenticular altocumulus clouds are formed on the crests of waves created by barriers in the wind flow - can be caused by mountain waves. They are an indication of very strong turbulence.
Aviation Weather (AC 00-6) Ch. 13
Low-level turbulence can occur and icing can become hazardous in which type of fog?
**Steam fog.** Steam fog forms in winter when cold, dry air passes over comparatively warm water. The result is low level turbulence and icing. Aviation Weather (AC 00-6) Ch. 16
One in-flight condition necessary for structural icing to form is
visible moisture.
One of the two conditions for structural icing to form is the aircraft must be flying through visible moisture.
Aviation Weather (AC 00-6) Ch. 19
Which conditions result in the formation of frost?
The temperature of the collecting surface is at or below the dewpoint of the adjacent air and the dewpoint is below freezing.
Frost forms in much the same way as dew. The difference is that the collecting surface must be colder than the dew point of the surrounding air and the dew point must be colder than freezing.
Aviation Weather (AC 00-6) Ch. 3
What situation is most conducive to the formation of radiation fog?
Warm, moist air over low, flatland areas on clear, calm nights.
Favorable conditions for radiation fog are: clear sky, at night or near daybreak, little or no wind and a small temperature / dew point spread.
Aviation Weather (AC 00-6) Ch. 16
(Refer to figure 18.) Of what value is the Weather Depiction Chart to the pilot?
For determining general weather conditions on which to base flight planning.
The weather depiction chart gives a broad overview of the observed flying category conditions at the valid time of the chart.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 4
(Refer to figure 14.) The intensity and type of icing reported by a pilot is
light to moderate rime.
The PIREP reports as /IC LGT-MOD RIME 072-089. Light to moderate rime icing from 7,200’ to 8,900’.
Aeronautical Information Manual (AIM) 7-1
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 3
In which situation is advection fog most likely to form?
An air mass moving inland from the coast in winter.
Advection fog forms when moist air moves over colder ground or water.
Aviation Weather (AC 00-6) Ch. 16
(Refer to figure 19.) How are Significant Weather Prognostic Charts best used by a pilot?
For determining areas to avoid (freezing levels and turbulence).
Fronts, precipitation, freezing levels, and turbulence found on the significant weather prognostic chart can provide the pilot with insight on areas to avoid. Looking at charts for multiple time periods allows the pilot to see how these areas will change.
Aviation Weather Services (AC 00-45) Ch. 5
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Clouds are divided into four families according to their
height range.
The four basic cloud types are divided into four families, high, middle, low, and clouds with extensive vertical development.
Aviation Weather (AC 00-6) Ch. 13
(Refer to figure 14.) The base and tops of the overcast layer reported by a pilot are
7,200 feet MSL and 8,900 feet MSL.
The PIREP gives sky cover after the SK symbol. It describes cloud amount, MSL height of cloud bases, and MSL height of cloud tops. The overcast layer, OVC072-TOP089, is 7,200’ MSL and 8,900’ MSL.
Aeronautical Information Manual (AIM) 7-1
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 3
(Refer to figure 15.) In the TAF for KMEM, what does ‘SHRA’ stand for?
Rain showers.
3SM SHRA means three miles visibility in rain (RA) showers (SH).
Aviation Weather Services (AC 00-45) Ch. 5
Aeronautical Information Manual (AIM) 7-1
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
If you will be flying with cumulus clouds, you might expect:
A bumpy flight with good visibility.
Since air is rising to form a cumulus cloud the air is bumpy but the visibility is normally good.
Pilot’s Handbook of Aeronautical Knowledge Ch. 12
(Refer to figure 15.) The only cloud type forecast in TAF reports is
**Cumulonimbus.** Cumulonimbus clouds (CB) are the only cloud type forecast in TAFs. [Aeronautical Information Manual (AIM) 7-1](https://dl.videos.sportys.com/onlinecourse/documents/references/aim_ch7.pdf) [Aviation Weather Services (AC 00-45) Ch. 5](https://dl.videos.sportys.com/onlinecourse/documents/references/AC_00_45H_with_Chg_1_Chapter_5.pdf)
If you read in a METAR the symbols “SKC” and “OVC”, refer to:
Sky Clear and Overcast.
“SKC” indicates Sky cover is clear. “OVC” indicates sky cover is overcast.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
(Refer to figure 12.) The wind direction and velocity at KJFK is from
180° true at 4 knots.
KJFK is reporting the wind direction and speed as 18004KT. This means that the wind direction (first three digits) is from 180 true at (last two digits) 04 knots.
Aviation Weather Services (AC 00-45) Ch. 3
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aeronautical Information Manual (AIM) 7-1
Thunderstorms reach their greatest intensity during the
mature stage.
All thunderstorm hazards reach their greatest intensity during the mature stage.
Aviation Weather (AC 00-6) Ch. 19
What conditions are necessary for the formation of thunderstorms?
High humidity, lifting force, and unstable conditions.
For a cumulonimbus (thunderstorm) cloud to form, it must have sufficient water vapor, an unstable lapse rate, and an initial upward boost.
Aviation Weather (AC 00-6) Ch. 19
If the temperature/dewpoint spread is small and decreasing, and the temperature is 62 °F, what type weather is most likely to develop?
Fog or low clouds.
Favorable conditions for radiation fog are: clear sky, at night or near daybreak, little or no wind and a small temperature / dew point spread.
Aviation Weather (AC 00-6) Ch. 16
Clouds, fog, or dew will always form when
water vapor condenses.
Clouds, fog, and dew are all forms of visible moisture which occur when invisible water vapor condenses into its liquid form.
Aviation Weather (AC 00-6) Ch. 3
What values are used for Winds Aloft Forecasts?
True direction and knots.
The FD contains a six-digit group comprised of wind direction (first two digits) in reference to true north, wind speed (second two digits) in knots, and temperature (last two digits) in degrees Celsius.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
Aviation Weather Services (AC 00-45) Ch. 5
Aeronautical Information Manual (AIM) 7-1
To get a complete weather briefing for the planned flight, the pilot should request
a standard briefing.
A standard briefing is a comprehensive weather briefing. It includes all the necessary information the pilot needs to plan his flight.
Aeronautical Information Manual (AIM) 7-1
Aviation Weather Services (AC 00-45) Ch. 1
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
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.
Hazardous turbulence is present in all thunderstorms. Outside the cloud, shear turbulence has been noted as much as 20 miles laterally from a severe storm.
Aviation Weather (AC 00-6) Ch. 19
(Refer to Figure 17.) Determine the wind and temperature aloft forecast for ALS at 12,000 feet.
260° true at 35 knots, temperature -8°C.
“2635-08” at ALS indicates the wind from 260° true at 35 knots, with a temperature of -8° Celsius.
Pilot’s Handbook of Aeronautical Knowledge Ch. 13
If you are on approach and picking up ½ in. of rime ice on the leading edge of your wings, you should consider:
A faster than normal approach and landing speed.
Ice accumulates unevenly on the airplane. It adds weight and drag (primarily drag) and decreases thrust and lift. With ice accumulations, Ice adds weight and drag and decreases thrust and lift. The landing approach should be made with more speed. a minimum wing flap setting and with an added margin of airspeed.
Instrument Flying Handbook Ch. 4