Meterology and Weather Services Flashcards
What is the minimum glycol content of Type 1 deicing/anti-icing fluid
80%
The stability of an air mass can usually be determined by
Cloud types and the type of precipitation
A jet stream is a narrow, shallow, meandering river of maximum winds extending around the globe in a wavelike pattern with speeds of
50 knots or greater
A severe thunderstorm is one in which the surface wind is
58 mph or greater and or surface hail is 3/4 inch or more in diameter
Low pressure area are areas of
Ascending air
If a sample of air is forced upward and it is colder than the surrounding air, it
Sinks until it reaches denser air
You are approaching an airport to land in 20 minutes. The METAR reports temperature 10 degrees C, dew point 10 degrees C, winds 310 at 4 and scattered clouds with rain. You expect
Radiation fog
Referring to figure, what was the cloud ceiling at Walnut Ridge (KARG)?
Overcast 1,000 feet AGL
Where are jet streams normally located?
In a break in the tropopause where intensified temperature gradients are located.
Which type of storms are most likely to produce funnel clouds or tornadoes?
Cold front or squall line thunderstorms
Which conditions result in the formation of frost?
Temperature of the collecting surface is below the dew point and the dew point is also below freezing
Freezing rain encountered during climb is normally evidence that
A layer of warmer air exists above
Referring to the figure, what condition is reported at Dallas (KDAL)?
Altimeter setting is 30.07”
An aircraft that encounters a headwind of 40 knots, within a microburst, may expect a total shear across the microburst of
80 knots
An aircraft that encounters a headwind of 45 kn within a micro burst may expect a total shear across the micro burst of
90 kn
What is the definition of severe wind shear?
Any rapid change in one direction or velocity which causes air speed changes greater than 15 kn or vertical speed changes greater than 500 feet per minute.
Referring to the figure what approximate wind direction speed and temperature are expected for a flight over OKC at flight level 370?
Interpolating, it’s 260 true 27 knots, ISA 6 Celsius
Forecast winds and temperatures aloft for an international flight may be obtained consulting what?
Wind and temperature loft charts prepared by the US national centers of environmental prediction (NCEP)
Which type of clouds may be associated with the jetstream?
Cirrus clouds on the equatorial side of the jetstream
A squall is a sudden increase of at least 15 kn in average wind speed to sustained speed of
20 kn or more for at least one minute
Which INITIAL flight deck indication should a Pilot be aware of when I headwind shears to a calm wind?
Indicated airspeed decreases, aircraft pitches down, and altitude decreases.
Which is a necessary condition for the occurrence of a low level temperature inversion windshield?
A calm or light wind near the surface and a relatively strong wind just above the inversion.
Which primary source contains information regarding the expected weather at the destination airport, at the ETA?
Terminal aerodrome forecast (TAF)
Which process causes adiabetic cooling?
Expansion of air as it rises.
The $symbol at the end of the following METAR indicates that
Maintenance is needed on the system
Which conditions are necessary for the formation of upslope fog?
Moist stable air being moved over gradually rising ground by a wind.
What weather is predicated by the term VCTS in a terminal aerodrome forecast
Thunderstorms are expected in the vicinity
Referring to the figure what effect will a microburst encounter have upon the aircraft in position 4
Strong tailwind
SPECI KGLS 131802Z 10012G21KT 060V140 2SM +SHRA SCT005 BKN035 OVC050CB 24/23 A2990 RMK RAB1757 WS TKO RW09L WSHFT 58 FROPA
This SPECI report at Galveston indicates which condition?
Precipitation started at 1757. The remark, RAB1757 indicates rain began at 57 minutes past the hour.
Referring to the figure, what will be the wind and temperature trend for a DEN ICT OKC flight at 11,000 feet?
Wind speed increase slightly interpolation of the forecast for 9000 and 12,000 feet yield a forecast demonstrating such
Clear ice, generally forms in outside temperature ranges of
Zero to -10°C
The tropopause is generally found when the free air temperatures are
Between -55°C and -65°C
Which type of icing is associated with the smallest size of water droplet similar to that found in low level stratus clouds?
Rime ice
What is a characteristic of the troposphere?
There is an overall decrease of temperature with an increase of altitude
Jet streams are strongest during which season in the northern hemisphere
Winter
What characterizes a ground based inversion
Poor visibility
Vertical windshear can be determined by comparing winds on vertically adjacent, constant pressure charts. The vertical wind share that is critical for probability of turbulence is.
6 kn or more per 1000 feet
What action is required prior to takeoff if snow is adhering to the wings of an air carrier airplane?
Assure that the snow is removed from the airplane
Where is a common location for an inversion?
In the stratosphere
How can the stability of the atmosphere be determined?
Ambient temperature lapse rate
Snow on top of deicing or anti-icing fluids
Must be considered as a adhering to the aircraft
I saw bars on a surface weather chart represent lines of equal pressure
Reduced to sea level
I saw bars on a surface weather chart represent lines of equal pressure
Reduced to sea level
Which windshear condition results in a loss of air speed?
Decreasing headwind and increasing tail wind.
When will frost most likely form on aircraft surfaces?
On clear nights with stable air and light winds.
Referring to map what is the forecast wind direction speed and temperature over KELY at 30,000 feet?
220°, 35 kn, -33°C
Temperature and radiation variations over land with a clear sky typically lead to what
Incoming terrestrial radiation peeking at noon
Referring to the figure what type of report is listed for Laibach KLBB at 1818 Zulu time?
An aviation selected special weather report SPECI
When does minimum temperature normally occur during a 24 hour? Period?
After sunrise
A study state thunderstorm is associated with what
Weather systems
Which is an effect of ice snow or frost formation on an airplane
Decreased angle of attack for stalls
Which action is recommended if jetstream turbulence is encountered with a direct headwind or tailwind?
Change altitude or course to avoid a possible change elongated, turbulent area.
The peak wind at KAMA was reported to be 320° true at 39 kn which
Occurred at 1743 Zulu time
The horizontal windshield critical for turbulence, moderate or greater for 150 miles
Is greater than 18 kn
Which wind share condition results in an increase in air speed
Decreasing tail, wind and increasing headwind
The purpose of diluting ethylene glycol fluid with water and non-precipitation conditions is
To decrease the freeze point
Which weather condition is defined as an anti-cyclone
High-pressure area
What course of action should a pilot take if encountering freezing rain
Climb because the temperature is warmer at a higher altitude
If involved in a micro person encounter in which aircraft positions will the most severe downdraft occur
Positions three and four
Clear air turbulence associated with a mountain wave may extend as far
As 5000 feet above the tropopause.
The threshold wind speed in the jetstream for clear air turbulence is generally considered to be
110 kn
What weather condition occurs at the altitude where the dewpoint lapse rate and the dry adiabatic lapse rate converge?
Cloud bases form
What is the result when water vapor changes to the liquid state while being lifted in a thunderstorm?
Latent heat is released to the atmosphere
If the Windsor loft are blowing parallel to the front,
The front move slowly, if at all
What was the local central time of the aviation routine weather report at Austin?
11:53 AM
Which type of cloud is associated with violent turbulence and tendency toward the production of funnel clouds?
Cumulonimbus mammatus
In the international terminal aerodrome forecast a variable wind direction is noted by VRB where the three digit direction usually appears a common wind appears in the TAF
As 0000KT
Which change took place at Wichita Falls between 1757 and 1820 UTC
A funnel cloud was observed
Which term applies when the temperature of the air changes by compression or expansion with no heat added or removed?
Adiabatic
Atmospheric pressure changes due to the thunderstorm will be at the lowest value
When the thunderstorm is approaching
Which Arctic flying hazard is caused when a cloud layer of uniform thickness overlays a snow or ice covered surface?
White out
What condition is indicated when ice pellets are encountered during flight?
Freezing rain at higher levels
Used to obtain the meter at Tyler KTYR at 1753 Zulu
Automated surface observing system a SOS, having a precipitation discriminator
Freezing point depressant FPD fluids are highly soluble in water, however
Isis slow to absorb it and to melt when it contact with it
Sheer turbulence from a thunderstorm has been encountered
20 miles from the severe thunderstorm
What action is recommended when encountering turbulence due to a wind shift associated with a sharp pressure trough?
Establish a straight course across the storm area
What are the only cloud types forecast in a TAF
Cumulonimbus CB
Which procedure increases holding time when deicing/ anti-icing an airplane using a two step process?
Heated Type 1 fluid followed by cold Type 2 fluid. Type 2 fluid is applied cold to increase its thickness and increase holding time.
Which condition is present when a local parcel of air is stable?
The parcel of air resists convection
When flying over the top of a severe thunderstorm, the cloud should be overflown by at least
1,000 feet for each 10 knots wind speed
Referring to the figure, what will be the wind and temperature trend for a DSM LIT SHV flight at 12,000 feet?
Wind speed decreases
The rate of decrease in wind speed from the jet stream core is considerably greater on the
Polar side
What is indicated about an air mass if the temperature remains unchanged or decreases slightly as altitude is increased?
The air is stable
What type weather conditions are covered in the convective SIGMET
Embedded thunderstorms, lines of thunderstorms, and thunderstorms with 3/4 inch hail or tornadoes
You are planning to arrive at the KHOU airport at 0900Z, what conditions can be expected as indicated by this TAF:
KHOU 151720Z 1518/1618 22009KT P6SM SCT030 SCT250
FM160000 18005KT P6SM
Thunderstorm activity 5 to 10 miles from the airports runway complex
What is an important characteristic of wind shear
It may be associated with either a wind shift or a wind speed gradient at any level in the atmosphere
What is a likely location of clear air turbulences?
In an upper trough on the polar side of a jet stream
All ATC facilities using radar weather processors with the ability to determine precipitation intensities will describe the intensity as
Light, moderate, heavy, intense, extreme or severe
What information from the control tower is indicated by the following transmission?
SOUTH BOUNDARY WIND ONE SIX ZERO AT TWO FIVE, WEST BOUNDARY WIND TWO FOUR ZERO AT THREE FICE
There is a possibility of wind shear over or near the airport
What change has taken place in the meter SPECI report
Thundershowers began at 12 minutes past the hour
Convective clouds which penetrate a stratus layer can produce which threat to instrument flight
Embedded thunderstorms
A clear area in a line of thunderstorm echoes on a radar scope indicates
An area where precipitation drops are not detected
When flying in the rain and an air temperature of 1 degree Celsius, a pilot should
Be aware of the possibility of airframe icing
Which area or areas of the northern hemisphere experienced generally east to west movement of weather systems?
Arctic and subtropical
Referring to the figure what condition is reported at Childress (KCDS)
Light rain showers
What is the primary cause of all changes in the earths weather?
Variations of solar energy at the earths surface
What is the effect of freezing point depressant FPD fluid residue on engine fan or compressor blades?
It can reduce engine performance and cause surging and or compressor stalls
Referring to the figure what approximate wind direction speed and temperature relative to ISA are expected for a flight over MKC at flight level 260
260 true 43 knots, ISA +10 Celsius
Airborne weather radar is installed to help the crew
Avoid severe weather
Which weather condition is present when the tropical storm is upgraded to a hurricane
Sustained winds of 65 knots or more
Referring to the figure, how will the aircraft in position 4 be affected by a microburst encounter?
Performance decreasing with a tailwind and downdraft
What is a difference between an air mass thunderstorm and a steady state thunderstorm
Air mass thunderstorm downdrafts and precipitation retard and reverse the updrafts
Maximum downdrafts in a microburst encounter can be as strong as
6,000 feet per minute
Which condition would initially cause the indicated airspeed and pitch to increase and the sink rate to decrease
Sudden increase in a headwind component
What is the general direction of movement of a hurricane located in the Caribbean or Gulf of Mexico region?
Northwesterly curving to northeasterly
Which initial flight fact indications should a pilot be aware of when a constant headwind shears to a calm wind?
Altitude, pitch, and indicated airspeed decrease
Which of the following weather conditions are conducive to inflight icing?
Visible rain with temperatures below 0 degrees C
Which type of weather can only be directly observed during flight and then reported in a PIREP
Turbulence and structural icing
Clear air turbulence associated with a jet stream is
Most commonly found in the vicinity of the tropopause
A flight is scheduled at daybreak. The current weather is rainy but is expected to clear, with temperature/ dew point spread forecast to be 10 degrees C / 10 degrees C and winds 330 at 5 knots. What weather conditions should you expect?
These conditions could produce radiation fog?
Under what conditions would clear air turbulence most likely be encountered
When constant pressure charts show 20 knot isotachs less than 150nm apart
What is indicated by the following report?
TYR UUA/OV TYR180015/ TM 1757/FL310/ TP B737/TB MOD-SEV CAT 350-390
An urgent pilot report for moderate to severe clear air turbulence
Large areas of land
Tend to increase temperature variations
A station is forecasting wind and temperature aloft to be 280 degrees at 205 knots; temperature -51C at FL390. How would this data be encoded in the FB?
789951 - FB forecasts of wind speeds from 100 knots through 199 have 50 added to the wind direction code and 100 subtracted from the speed. Winds over 200 knots are coded as 199 knots.
What type clouds are indicative of very strong turbulence
Standing lenticular
What type turbulence should be reported when it causes slight rapid and somewhat rhythmic bumpiness without appreciable changes in attitude or altitude, less than one third of the time?
Occasional light chop
During an ifr cross country flight you picked up time icing which you estimate is 1/2” thick on the leading edge of the wings. You are now below the clouds at 2,000 feet AGL and are approaching your destination airport under VFR. Visibility under the clouds is more than 10 miles, winds at the destination airport are 8 knots right down the runway, and the surface temperature is 3 degrees C. You decide to
Use a faster than normal approach and landing speed.
The VV001 in the following METAR indicates
KFSM 131756Z AUTO 000000kt m1/4sm r25/0600V1000ft -ra fg vv001
A2989 rmk a02 vis 3/4 rwy19 chino rwy19 $
A 100 foot indefinite ceiling
If a sigmet alert is announced, how can information contained in the sigmet be contained
By contacting the nearest flight service
Where do squall lines most often develop?
Ahead of a cold front
Freezing point depressant FPD fluid residue in engine can’t or compressor blades
Can reduce engine performance and cause surging and or compressor stalls
Which event usually occurs after an aircraft passes through a front into the colder air?
Atmospheric pressure increases
Which is the expected duration of an individual microburst
Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation
Referring to the figure, what is the forecast temperature at ATL for the 3,000 ft level?
Not reported
When high level moisture is available, cirrus clouds form on the
Equatorial side of the jet stream
What is the recommended technique to counter the loss of airspeed and resultant lift from wind shear?
Maintain, or increase, pitch attitude and accept the lower than normal airspeed indications
Steep frontal surfaces are usually associated with
Fast moving cold fronts
What should the de-ice/anti ice fluid temperature be during the last step of a two phase process?
Cold
Where is the normal location of the jet stream relative to surface lows and fronts?
The jet stream is located north of the surface systems.
A cyclone is
A hurricane force storm in the Indian ocean
Which atmospheric factor causes rapid movement of surface fronts?
Upper winds blowing across the front
During the life cycle of a thunderstorm, which stage is characterized predominantly by downdrafts?
Dissipating
What is the lowest cloud in the stationary group associated with a mountain wave?
Rotor cloud
Which of the following will decrease the holding time during anti icing using a two step process
Apply heated type two fluid
Turbulence encountered above 15,000 feet AGL not associated with cloud formations, should be reported as
Clear air turbulence
When you hear a SIGMET on an atc frequency forecasting severe icing constituents on the route to your destination, you plan for
The possibility of freezing rain and freezing drizzle that can accumulate in and beyond the limits of any deicing or anti icing equipment
The PROB40 HHhh group in an international TAF indicates the probability of
Thunderstorms or other precipitation
Where is the usual location of a thermal low?
Over the surface of a dry, sunny region
Constant pressure analysis charts contain contours, isotherms, and some contain isotachs. The contours depict
Ridges lows troughs and highs aloft
In comparison to an approach in a moderate headwind, which is an indication of a possible wind shear due to a decreasing headwind when descending on the glide slope
Higher pitch attitude is required
Which type of jet stream can be expected to cause the greater turbulence?
A curving jet stream associated with a deep low pressure trough
Test data indicate that ice, snow, or frost having a thickness and roughness similar to medium or coarse sandpaper on the leading edge and upper surface of a wing can
Reduce lift by as much as 30 percent and increase drag by 40 percent
Adiabatic warming is also described as
Compressional heating
What will be the wind and temperature trend for an STL MEM MSY flight at FL 330
Wind speed decrease
What weather feature occurs at altitude levels near the tropopause
Maximum winds and narrow wind shear zones.
What is indicated by the term embedded thunderstorms
Thunderstorms are obscured by other types of clouds
This pilot report at Fort Worth indicates
The ceiling at KDFW is 6,000 feet
Weather conditions expected to occur in the vicinity of the airport but not at the airport are denoted by the letters V(C). When V(C) appears in a TAF it covers an area of
A 5 to 10 statute mile radius from the airport.
Maximum turbulence potential charts (GTG-2) are issued
Hourly
In which meteorological conditions can frontal waves and low pressure areas form?
Slow-moving cold fronts or stationary fronts.
The prevailing visibility in the following METAR is
Less than 1/4 statute mile
Why are downdrafts in a mature thunderstorm hazardous
Downdrafts are kept cool by cold rain which tends to accelerate the downward velocity
Cumulus clouds often indicate
Possible turbulence
What type turbulence should be reported when it is momentarily causes slight, erratic changes in altitude and or attitude one third to two thirds of the time?
Intermittent light turbulence
Dew point fronts result from
Air density differences due to the humidity levels
Which weather condition is an example of a non frontal instability band
Squall line
How does coriolis force affect wind direction in the southern hemisphere ?
Causes clockwise rotation around a low
Which weather condition is indicated by this METAR report at midland
Rain of unknown intensity ended 16 minutes before the hour
What hazard should you expect for a morning departure from KPDX, based on this METAR?
KPDX 271154Z 0000kt 9sm clr-10/-10 a2979
Frost on the aircraft
Referring to the figure what approximate wind direction speed and temperature relative to ISA are expected for a flight over TUS at FL 270
010 true 5 knots ISA +13C
What information is provided by a connective outlook (AC)
It provides prospects of both general and severe thunderstorm activity during the following 24 hours
Which system in the convective SIGMET listing has the potential of producing the most severe storm?
The isolated storm 50 miles northeast of Memphis (MEM)
What term describes an elongated area of low pressure?
Trough
What is a feature of supercooled water
The unstable water drop freezes upon striking an exposed object
What condition produces the most frequent type of ground or surface based temperature inversion
Terrestrial radiation on a clear relatively calm night
Even a small amount of frost ice or snow may
Hinder lift production to a point where takeoff will be impossible
At which location does Coriolis force have the least effect on wind direction
At the equator
Anti icing fluid should provide freezing point protection to
-20 F ambient temperature
Which type of frontal system is normally crossed by the jet stream
Occluded front
When penetrating a microburst, which aircraft will experience an increase in performance without a change in pitch power?
1
What weather improvement was reported at Lubbock between 1750 and 1818 utc
The vertical visibility improved by 2,000 feet
What is the approximate rate unsaturated air will cool flowing upslope
3 degrees Celsius per 1,000 feet
You are planning a flight to the west coast of the United States, which is currently below the published weather minimums for an ILS approach to that airport. Winds are forecast to increase to above 20 knots from the west at your scheduled arrival time. What weather conditions should you expect?
A layer of low stratus or stratocumulus is expected
What is the expected duration of an individual microburst
Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation.
Where can the maximum hazard zone caused by wind shear associated with a thunderstorm be found?
On all sides and directly under the thunderstorm cell.
Doppler wind measurements indicate that the wind speed change a pilot may expect when flying through the peak intensity of a microburst is approximately
45 knots
What is the minimum glycol content of type 2 deicing anti icing fluid
50 percent
What sources reflect the most accurate information on current and forecast icing conditions
AIRMET ZULU
Volcanic Ash advisory charts are updated every
6 hours
What wind direction and speed aloft are forecast by this WINDS AND TEMPERATURE ALOFT FORECAST (FD) for FL390 - ‘750649’
250 at 106 knots
Data that may be added manually weather augmentation to the automated weather observing service report is limited to
The precipitation accumulation report, an automated variable visibility, and wind direction remark
Frozen dew is
Hard and transparent
A strong wind shear can be expected
On the low pressure side of a 100 knot jetstream core
What is a feature of air movement in a high pressure area
Descending to the surface and then outward
Clouds with extensive vertical development over mountainous terrain are a sign of
An unstable airmass
Precipitation induced fog
Results from relatively warm rain or drizzle falling through cooler air
What weather difference is found on each side of a dry line
Dew point difference
Which airplane performance characteristics should be recognized during takeoff when encountering a tailwind shear that increases in intensity
Loss of, or diminished, airspeed performance
Which type precipitation is an indication that supercooled water is present?
Freezing rain
A calm wind that is forecast in the international TAF is encoded as
0000kt
Maximum downdrafts in a microburst encounter are strong and may include horizontal winds near the surface as strong as
45 knots
When structured air moves downhill its temperature increases
At a slower rate than dry air because vaporization uses heat
Embedded thunderstorms which can be hazardous during instrument flight are most likely to occur
In a warm front occlusion
What condition is necessary for the formation of structural icing in flight
Visible water
Freezing point depressant fluids used for de icing
Are intended to provide ice protection on the ground only
What effect will a microburst encounter have upon the aircraft in position 3
Strong downdraft
Maximums downdrafts in a microburst encounter may be strong as
6,000 feet per minute
What features is normally associated with the cumulus stage of a thunderstorm
Continuous updraft
What wind direction and speed aloft are forecast by this FD for FL390 -731960-
230 at 119 knots
Summer thunderstorms in the arctic region will generally move
Northeast to southwest in polar easterlies
