ADX - WX Flashcards
What weather phenomena signals the beginning of the mature stage of a thunderstorm
The start of rain at the surface
During the life cycle of a thunderstorm, which stage is characterized predominantly by downdraft?
dissipating
What feature is normally associated with the cumulus stage of a thunderstorm?
Continuous updraft
Where do squall lines generally start?
Ahead of a cold front
Why are downdrafts in a mature thunderstorm hazardous?
Downdrafts are kept cool by cold rain, which tends to accelerate downward velocity
Difference between an air mass thunderstorm and a steady state thunderstorm?
Air mass thunderstorm, downdrafts and precipitation, retard, and reverse the up drafts
What type of storms are most likely to produce funnel clouds or tornadoes?
Cold front or squall line thunderstorms
When flying over the top of a severe thunderstorm, the cloud should be overflown by at least
1000 feet for each 10 kn wind speed.
Which weather condition is an example of a non-frontal instability band
Squall line
Steady state thunderstorms are usually associated with?
Weather systems
Shear turbulence from a thunderstorm has been encountered?
20 miles from the severe thunderstorms.
Downdrafts and the thunderstorm can be expected to exceed
2500 feet per minute
Up drafts in the mature stage of a thunderstorm can exceed?
6000 feet per minute
Storm gust fronts often move as much as?
15 miles ahead of the associated precipitation.
Downdrafts in a thunderstorm may exceeded
24 knots
Embedded thunderstorms are most likely to occur
In a warm front occlusion
Turbulence encountered above 15,000 feet AGL not associated with cloud formations should be reported as?
Clear air turbulence (CAT)
A strong wind shear can be expected
On the low pressure side of a 100 knot jetstream core
What is a likely location of clear air turbulence?
In an upper trough on the polar side of a jetstream.
Where do the maximum winds associated with the jetstream usually occur?
In the vicinity of breaks in the tropopause on the polar side of the jet core
The rate of decrease of wind speed from the jetstream core is considerably greater on the
Polar side
What type of jetstream can be expected to cause the greatest turbulence?
A curving jetstream associated with a deep low pressure trough
What weather feature occurs at altitude levels near the tropopause?
Maximum wind and narrow wind shear zones.
Where are jet streams normally located?
In a break in the tropopause where intensified temperature gradients are located.
Under what conditions would clear air turbulence, most likely be encountered?
When constant pressure charts showed 20-knot isotachs less than 150 nautical miles apart.
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/trough
Where is the normal location of the jetstream relative to surface lows and fronts?
The jetstream is located north of the surface systems
What type of frontal system is normally crossed by the jetstream?
Occluded front
What type of clouds may be associated with the jetstream?
Cirrus clouds on the equatorial side of the jetstream.
Which action is recommended if jetstream turbulence is encountered with the direct headwind or tailwind
Change altitude or course to avoid a possible elongated turbulent area
Which action is recommended regarding an altitude change to get out of jetstream turbulence?
Descend, if ambient temperature is falling.
The jetstream is a river-like flow of high altitude, wind following the planetary atmospheric wave patterns with speeds of?
50 knots or greater
An upper level wind cannot be considered a jetstream, unless the wind speed is at least?
50 knots
Clear air turbulence (CAT) associated with the jetstream is?
Most commonly found in the vicinity of the tropopause.
There are 3 jetstreams….?
Polar front, subtropical and the polar night jet streams.
The threshold wind speed in the jetstream for clear air turbulence is generally considered to be
110 knots
In the mid latitudes, wind speed in the jetstream averages considered less in the?
Summer
Jet streams are strongest during which season in the northern hemisphere?
Winter
Where does the highest wind shear exist associated with the jet-stream?
Near the tropopause on the poleward side of the jet-stream.
Which area or areas of the hemisphere experience generally east to west movement of weather systems
Arctic and subtropical
Summer thunderstorms in the Arctic region will generally move
Northeast to southwest in Polar easterlies
A cyclone is similar to a tropical storm in (????)
The Indian ocean with winds of 64 Knots or more*
- the tropical storm has winds of 34 to 63 kn
Gusts in tropical cyclones connect to the average one minute wind speed by as much as
50%
Tropical depression has formed when
The highest sustained winds have reached 33 knots
What is the characteristic of the troposphere?
There is an overall decrease of temperature with an increase in altitude
Which feature is associated with the tropopause
Abrupt change of temperature lapse rate
The tropopause is generally found when the free air temperatures are
Between -55 Celsius and 65 Celsius
The tropopause varies in height from
20,000 feet or below at the poles to 65,000 thousand feet at the equator
Where is a common location for an inversion?
In the stratosphere
What condition produces the most frequent type of ground or surface based temperature inversion
Terrestrial radiation on a clear, relatively calm night
What condition produces the most frequent type of ground or surface based temperature inversion
Terrestrial radiation on a clear, relatively calm night
What term applies when the temperature of the air changes by compression or expansion with no heat added or removed?
Adiabatic
What is the approximate rate unsaturated air will cool flowing up slope
3°C per 1000 feet
What is the approximate rate unsaturated air will cool flowing up slope
3°C per 1000 feet
Which process causes adiabatic cooling
Expansion of the air as it rises
Adiabatic warming is also described as
Compression heating
What is a feature of air movement in a high-pressure area?
Descending to the surface and then outward
Where is the usual location of a thermal low?
Over the surface of a dry, sunny region.
What is corrected altitude (approximate true altitude)?
Indicated altitude corrected for temperature variation from standard.
Low pressure areas or areas of?
Ascending air
If the ambient temperature is warmer than standard at Flight level 350 what is the density altitude compared to pressure altitude?
Higher than pressure altitude
If the ambient temperature is colder than standard at FL310, what is the relationship between true altitude and pressure altitude
True altitude is lower than 31,000 feet
Which pressure is defined as station pressure?
Actual pressure at field elevation,
Isobars on a surface weather chart represent lines of equal pressure
Reduced to sea level
When the temperature is -20 Celsius at 15,000 feet indicated, you know that?
The altimeter is indicating higher than true altitude.
Given :
PA = 1.000ft
True air temperature = 10°C.
From the conditions given the approximate density altitude is?
650 feet MSL
At lower levels of the atmosphere, friction causes the wind to flow across isobars into a low because the friction
Decreases wind, speed, and Coriolis force
Which type wind flows down slope, becoming warmer and dryer?
Katabatic wind
At which location does Coriolis forest have the least effect on wind direction?
At the equator
Land surface heating on the coast results in?
A sea breeze
Land surface cooling on the coast results in?
A land breeze
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
Cloud formation is a process of?
Extensional cooling
How can the stability of the atmosphere be determined?
Ambient temperature laps rate
When saturated air moves downhill, its temperature increases?
At a slower rate than dry air because vaporization uses heat.
If a sample of air is forced upward, and it is colder than the surrounding air, it?
Sinks until it reaches denser air.
What is a feature of a stationary front?
Surface winds tend to flow parallel to the frontal zone.
Which event usually occurs after an aircraft passes through a front into the colder air?
Atmospheric pressure increases.
What weather change can be expected in an area where frontolysis is reported?
The front Is the dissipaating.
Which atmospheric factor causes rapid movement of surface fronts?
Upper winds blowing across the front.
In which meteorological conditions can frontal waves and low pressure areas form?
Slow moving cold fronts or stationary fronts.
What weather differences found on each side of a dry line?
Dewpoint difference
Dewpoint fronts result from
An air density difference due to the humidity levels
Dewpoint fronts are also called
Dry lines
Steep frontal surfaces are usually associated with?
Fast moving cold front
Shallow frontal surfaces tend to give?
Extensive cloudiness and large areas of precipitation.
When may has to just wind shear be expected?
In areas of low level, temperature, inversions, frontal zones, and clear air turbulence.
If the winds aloft are blowing across the front?
The front can be expected to move with the upper winds.
If the winds aloft are blowing parallel to the front?
The front moves slowly if it all.
Which is the definition of severe wind shear?
Any rapid change in Nguyen direction or velocity which causes airspeed changes greater than 15 kn or vertical speed changes greater than 500 feet/minute.
Which initial cockpit indications should a pilot be aware of when a headwind shears to a calm wind?
Altitude, pitch, and indicated airspeed decrease.
Which condition should initially cause the indicated airspeed and pitched to increase and the sink rate to decrease?
Sudden decrease in a headwind component.
Which initial cockpit indications should a pilot be aware of when a constant tailwind shears to a calm wind?
Altitude, pitch, an indicated airspeed increase.
Which is the recommended technique to counter the loss of airspeed and resultant lift from wind shear?
Maintain, or increase, pitch attitude, and except the lower than normal airspeed indications
Which windshield condition results in a loss of airspeed?
Decreasing headwind and increased in tailwind.
Which wind shear condition results in an increase in airspeed?
Decreasing tailwind and increasing headwind.
In comparison to an approach in a moderate headwind, which is an indication of a possible wind share due to a decreasing headwind when descending on the glideslope?
Higher pitch attitude is required.
Which airplane performance characteristics should be recognized during takeoff when encountering a tailwind shear that increases in intensity?
Loss of, or diminished, airspeed performance.
The rust is being managed to maintain desired, indicated airspeed, and the glide slope is being flown. Which characteristics should be observed when a tailwind shears to a constant headwind.
Pitch attitude: increases
Vertical speed: decreases
Airspeed: increases, then decreases
When thrust is being used to manage the glideslope, which characteristic should be observed when a headwind cheers to a constant tailwind
Decrease in pitch, increase in vertical speed, and loss of airspeed followed by on speed indications
How will increasing tailwind sheer affect aircraft performance on takeoff?
Airspeed will continue to decrease after the aircraft lifts off.
You can expect turbulence when winds?
Exceed 40 kn across the mountains.
Moderate CAT is considered likely?
When the vertical windshield is 5 kn per 1000 feet or greater and/or the horizontal wind shear is 40 kn per 150 miles or greater.
Which is one of the three key elements in an effective clear air turbulence avoidance system?
Dedicated planning/dispatch function.
What is the expected duration of an individual microburst?
Seldom longer than 15 minutes from the time the bird strikes the ground until dissipation
What is the expected duration of an individual microburst?
Seldom longer than 15 minutes from the time the bird strikes the ground until dissipation.
Microburst downdraft maximum winds, may be as strong as?
6000 ft./min.
An aircraft encounters, the headwind of 40 knots, with a microburst, may expect a total shear across the micro burst of?
80 knots
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
Which flight conditions of a large jet airplane create the most severe flight hazard by generating wingtip vertices of the greatest strength?
Heavy, slow, gear and flaps up.
How does the week turbulence vortex circulate around each wing tip?
Outward, upward, and around the wingtip.
Which statement is true concerning the weak turbulence produced by a large transport aircraft?
The vortex characteristics of any given aircraft may be altered by extending the flaps or changing the speed
To avoid the wind tip vertices of a departing jet airplane during takeoff, the pilot should?
Climb above and stay upwind of the jet airplanes flight path
If you takeoff behind a heavy jet that has just landed, you should plan to lift off?
Beyond the point where the jet touched down.
METAR UTC time is
Central Standard Time or 6 hours behind UTC
131753 = 13th day of month @ 1753 UUC or 1153 CST
METAR VV improved from M01 to
VV010 30 = improved by 2000 ft
METAR KCDS -SHRA
Light rain showers
METAR KDAL - A3007
Altimeter setting = 30.07
METAR- KAMA Peak wind at.
RMK PK WND 32039 / 43 at 1743Z
METAR KGLS SPECI Reports…
RMK RAB57 = Rain began at 57 past the hour
Method used to obtain METAR at KTYR…
AUTO = ASOS (Automated Surface Observing System)
METAR - What weather condition reported at KMFA?
Rain of unknown intensity = RMK RAE44 (at 16 mins before the hour)
METAR - What change occurred at KSPS between 1757 and 1820 UTC?
FC - A funnel cloud was observed
How many hours behind Zulu time is Central Standard Time?
6 hours
1753 Zulu is 1153 CST
What does -SHRA mean?
Light rain showers
What does A3007 mean?
Altimeter setting is 30.07
METAR 131755Z … RMK PK WND 32039 / 43…
Peak wind at 320 degrees at 39 knots occurred 43 mins past the hour.
SPECI KGLS …..RMK RAB57…
Rain began 57 past the hour
METAR KTYR 131753Z AUTO…. What does AUTO mean?
Automated Surface Observing System (ASOS).
METAR KMAF … RMK RAE44?
Rain of unknown intensity ended at 16 minutes before the hour.
METAR KARG ….+RA OVC010 29/28? what was the ceiling?
1,000 feet AGL
METAR KFSM … M1/4SM …. $ What does M mean, and what is the visibility, and what is the $?
M = less
Visibility is M1/4SM = less than 1/4 mile
$ = maintenance needed
METAR KFSM …. -RA FG VV001 What does VV mean?
A 100-foot indefinite ceiling
A squall line is a sudden increase of at least (?)knots and speed rising to (?) or more for 1 minute or longer?
Wind speed of at least 16 knots, the speed rising to 22 knots or more for 1 minute or longer.
METAR KSFO … SLO993 6//// means?
Sea-level pressure of 999.3 hectopascals and an inderterminable amount of rain has occurred over the last 3 hours
When a trace/indeterminable amount of precipitation has occurred, then 4 forward slashes will follow a ‘6’ (6////).
Data that may be added to the AWOS is?
Thunderstorms (intensity and direction), precipitation (type and intensity), and obstructions to visibility (dependent on the visibility being 3 miles or less).
METAR KSFO … what does SLO993 SNINCR mean?
999.3 hectopascals and a snow depth of 10” and a 1” increase in the last hour.
What hazard should be expected at KPDX ….METAR ….CLR -10/-10 A2979?
Frost on the aircraft.
What type of turbulence should be reported when it causes slight, rapid, and somewhat rhythmic bumpiness without appreciable changes in attitude or altitude?
Occasional light chop.
What turbulence should be reported if it causes changes in attitude and/or altitude more than 2/3 of the time with the aircraft remaining in positive control at all times?
Continuous moderate turbulence.
What turbulence should be reported when it momentarily causes slight, erratic changes in attitude and/or altitude, one-third to two-thirds of the time?
Intermittent light turbulence.
The pilot reports what ceiling at KFTW? METAR … SCRI31-TOO043/BKN060-TOP085 /IVC097…
Believed to be 6,000 feet, but not sure. Cloud bases in PIREP’s are reported in MSL, unless otherwise indicated.
How is icing reported in a PIREP?
Rate of accumulation.
What is indicated by the following report?
TYR UUA/OV…MID-SEV CAT 350-399?
An urgent pilot report for moderate to severe CAT.
How would you receive in-flight weather for a destination 150 nm away?
Review the destination’s METAR and TAF through FIS-B.
FIS = Flight Information Services
How would you receive in-flight weather for a destination 150 nm away?
Review the destination’s METAR and TAF through FIS-B.
FIS = Flight Information Services
Enroute weather advisories should be obtained from FSS on?
122.2 MHz.
Volcanic ash advisories are updated every?
6 hours
What is the forecast temperature in the winds/temperature aloft forecast (FB) at 3,000 ft.
Never reported for 3,000 ft.
What is the wind direction and speed aloft for FL 390 - “750649”?
250 @ 106 knots
750 implies winds are over 100 knots or more. “50” is added for wind direction. 75-50 = 250, so wind direction is 250. adding to the “06” = 106 knots.
A station reports winds at 280 degrees at 205 knots. How would this be encoded in FB?
789951
“99” is used if winds are over 199 knots and 50 is added to the 2 digits.
ABI Winds and Temperature Aloft at FL330 = 2400833?
240 degrees, 08 knots, -33 degrees Celsius.
A PROB40 HHhh group in the International Terminal Aerodrome Forecast (TAF) indicates….
Thunderstorms or other precipitation.
Which primary source contains expected weather at the destination airport at the ETA?
Terminal Aerodrome Forecast
Weather conditions expected to occur in the vicinity of the airport, but not at the airport are denoted with “VC” in the TAF, and covers….?
A 5-10 statute mile radius from the airport.
Weather conditions expected to occur in the vicinity of the airport, but not at the airport are denoted with “VC” in the TAF, and covers….?
A 5-10 statute mile radius from the airport.
What are the only cloud types forecast in the TAF?
Cumulonimbus
What weather is predicted by “VCTS” in the TAF?
Thunderstorms are expected in the vicinity.
How is information from a SIGMET obtained?
By contacting the nearest FSS.
Which type of conditions are covers in a Convective SIGMET?
Embedded thunderstorms, lines of thunderstorms, and thunderstorms with 3/4” hail or tornadoes.
A severe thunderstorm has surface winds of…?
58 mph or higher and hail of 3/4” in diameter or more.
What sources reflect the most accurate information on current and forecast icing conditions?
PIREPs, AIRMET ZULUs, and SIGMETs
Convective SIGMETs are issued for a line of thunderstorms at least….?
60 miles long with thunderstorms affecting 40% of its length.
Convective SIGMETs are issued for severe thunderstorms….
Occurring for more than 30 mins of the valid period.
A SIGMET is issued when weather affects….?
3,000 square miles or more.
SIGMETs may not be valid for more than….?
4 hours for other phenomena.
The FAA’s Flight Information Services DataLink (FISDL) is designed to provide common frequency to flight crews from?
17,500 feet MSL down to 5,000 feet AGL.
The FISDL provides the following products?
METARs, SIGMETs, PIREPs, and AIRMETs.
What weather database can a dispatcher access concerning wind shear activity?
The Terminal Information for Pilot System (TWIP).
