Block 4 Flashcards
When are convective currents most active?
Warm summer afternoons
Which cloud form often produces widespread IFR weather?
Stratiform
WS identifies what?
SIGMET
How would you say 22015G25 180V250 ?
“Wind 220 at 15 gusts 25. Wind variable between 180 and 250.”
What is the raw material for clouds and precipitation?
Water vapor
What are the 3 types of structural icing?
Rime
Clear
Mixed
A layer in which temperature increases with altitude
Temperature inversion
What is issued when specified conditions are expected to affect at least 3,000 square miles?
SIGMET
Which 3 ingredients are required for the formation of precipitation?
Water Vapor
Lift
Growth Process
A boundary or transition zone between two air masses of different density and (usually) of different temperature is called _______.
A front
A sinking parcel of air compresses and _____ as it encounters increasing pressure; this causes a cloud to quickly ______.
Warms ; dissipate
What clouds resemble white fluffy cotton balls?
Cumuliform
What cloud may produce icing, turbulence and other hazards?
Cumuliform
Which gas constitutes only a small percentage of the earth’s atmosphere and varies widely in both time and space, ranging from trace amounts to 4% by volume?
Water vapor
A Maritime Tropical air mass is ______ and ______.
Warm and moist
The weather phenomena VA stands for:
Volcanic Ash
Water particles that reach the ground
Precipitation
What is a continental moisture?
Dry air mass that develops over land.
Air flow around a low:
Converges or Diverges
converges
Turbulent vertical motions that result from subsequent rising and sinking of air.
Convective Turbulence
The weather phenomena +FC stands for:
Funnel Cloud touching the ground (tornado or waterspout)
Which product would provide a forecast of IFR over Georgia and Atlanta?
AIRMET SIERRA
Which product would provide a forecast of sustained surface wind greater than 30 kts over Minnesota and Iowa?
AIRMET TANGO
A front that moves in such a way that warmer air replaces colder air.
Warm Front
The maximum valid period for a SIGMET is ____.
4 hours (or 6 hours outside continental US)
This type of turbulence causes abrupt changes in attitude or altitude. May be momentarily out of control.
Severe (SEV)
What is a maritime moisture?
Moist air mass which develops over water.
In regards to turbulence, what is “chop” and in what forms can it be reported?
Light or Moderate Chop
Bumpiness without appreciable changes in altitude or attitude
This type of icing may require occasional use of deicing equipment and will not present a problem if the deicing equipment is used.
Light (LGT)
How long are AIRMETs valid for?
No more than 6 hours
AIRMET SIERRAs are for:
IFR and mountain obscuration
Which type of front creates towering clouds?
Cold fronts
What are the elements listed on the PIREP form called?
Text Element Indicators (TEIs)
SIGMETs are issued for which weather phenomenas?
Any severe weather, widespread dust storms (DS), sandstorms (SS) or volcanic ash (VA).
The weather phenomena UP stands for:
Unknown Precipitation
Which front moves in such a way that warmer air replaces colder air?
Warm front
Rising air ______ and ______.
expands and cools
A downburst that covers an area greater than 2.5 miles alongside peak winds as high as 120 kts and can last from 5-30 minutes is called _______.
Macroburst
Which 3 systems alerts ATC of microbursts, wind shear and gust fronts?
LLWAS
TDWR (terminal doppler wx radar)
ASR/WSP (Weather system processor)
The weather phenomena GS stands for:
Small hail and/or snow pellets
What clouds indicate uplift of air?
Cumuliform
How would you say FEW000 if there are remarks explaining the obscurations?
“Sky partially obscured”
Highs have warm air which can hold more water vapor thus clouds tend to ________.
Evaporate
When is RVR reported?
When visibility is 1SM or less and/or
6000ft or less
How would you say R25L/M0800FT ?
“Runway 25L RVR less than 800.”
An RVR proceeded by a “P” (ex R16/P6000FT) means ______.
RVR is “More than” the number reported
Which produce would provide a forecast of severe icing over Kentucky?
SIGMET
How would you say: “KOKC 032203Z AUTO”
“Oklahoma City Airport Automated two two zero three Observation…”
Which precipitation type occurs when there is a shallow layer aloft with above freezing temperatures, with a deep layer of below freezing air at the surface?
Ice Pellets (PL)
How would you say R17L/2400V3000FT ?
“Runway 17L RVR variable 2400 to 3000.”
Convective SIGMETs are issued when severe thunderstorms have:
Winds >50kts
Hail 3/4” or greater
Tornatoes
What are the 4 classifications of turbulence?
Light (LGT)
Moderate (MOD)
Severe (SEV)
Extreme (EXTRM)
What will happen when the temperature-dew point spread decreases to zero?
The air becomes saturated and condensation will form dew or fog
This type of turbulence will cause the aircraft to move somewhat, but the aircraft will remain in positive control at all times.
Moderate (MOD)
What cloud is like a layer or blanket?
Stratiform
Are Convective SIGMETs scheduled or unscheduled?
Scheduled
Good visibility and turbulence are associated with ____ fronts.
Cold
Which layer of the atmosphere is stable and generally devoid of significant weather?
Stratosphere
Which of the following clouds would be visual proof of a mountain wave?
Rotor cloud
VV005 would be said as “________.”
“Indefinite Ceiling 500.”
What type of front has a steep slope which often leads to a narrow band of showers and thunderstorms if the rising air is unstable?
Cold front
In a TAF, what indicates a significant and rapid change?
FM
Within which layer of the atmosphere does temperature increase with altitude, making it a stable layer, generally devoid of significant weather?
Stratosphere
How would you say SCT000 if there are remarks explaining the obscurations?
“Sky partially obscured”
Snow lifted to a height of 6 ft or more above the ground reducing visibility to less than 7 SM
Blowing Snow
Ice that sticks to the outside of an airplane is called:
Structural icing
How would you say BKN000 if there are no remarks?
“Ceiling less than five zero broken”
A large body of air that has similar horizontal temperature and moisture characteristics defines _______.
Air Mass
The weather phenomena SG stands for:
Snow grains
What are the two commonly identified jet streams?
Polar Jet Stream
Subtropical Jet Stream
Although _______ is the most common type of icing, it is the least serious because it is easiest to remove.
Rime
The ratio of water vapor in the air compared to the amount of water vapor the air can hold at a particular temperature and pressure is the definition of _______.
Relative humidity
What level of turbulence do mountain waves produce?
Severe-Extreme
Rough, milky, opaque ice formed by the instantaneous freezing of small super-coolded water drops after they strike the aircraft
Rime ice
What is the standard temperature?
15 deg C, 59 deg F
In order to escape icing, a pilot must do what 3 things?
- Exit the area of visual moisture
- Climb or descend to positive temperatures
- Climb to altitudes where temperatures are too cold to support supercooled droplets
This type of turbulence causes slight, erratic changes in pitch/roll/yaw
Light (LGT)
What type of air mass produces stable air that is associated with smooth air, poor visibility and stratiform clouds?
Warm air over cold surface
Thunderstorm tops can commonly extend into the lower ________.
Stratosphere
The qualifier MI stands for:
Shallow
AIRMET ZULUs are for:
Icing/FreeZing
Wind direction is considered to be variable when during the 2-minute evaluation period, it fluctuates by 60 degrees or more.
Variable wind
The change of ice to water vapor is called ______.
Sublimation
Precipitation of transparent or translucent pellets of ice, which are round or irregular. Sometimes called “sleet”
defines _______.
Ice pellets (PL)
Turbulence is caused by these 3 things:
Convective currents
Obstructions to wind flow
Wind shear
What is the lowest and highest visibility that can be reported by an automated station?
M1/4SM and 10SM
An atmospheric wave disturbance formed when stable air flow passes over a mountain or mountain ridge
Mountain wave
What are the 3 temperature properties?
Arctic
Tropical
Polar
A _______ air mass moving over a _______ surface often produces unstable air associated with turbulence, good visibility, cumuliform clouds and showers.
cold ; warm
How would you say SCT000 if there are no remarks?
“Less than five zero scattered.”
The weather phenomena PY stands for:
Spray
_____ reduces horizontal visibility to less than 5/8 SM, but does not fall to the ground
Fog
The weather phenomena PL stands for:
Ice Pellets
A glossy, clear or translucent ice formed by the relatively slow freezing of large super-cooled water drops.
Clear ice
A strong downdraft which induces an outburst of damaging winds on or near the ground is a ______.
Downburst
The qualifier BC stands for:
Patches
This type of turbulence is violent and may be impossible to control/cause structural damage.
Extreme (EXTRM)
What is mixed ice?
A mixture of clear and rime ice
Air flow around a low converges in which direction, and has what type of motion?
Counter-clockwise; rises
This type of icing could be hazardous even after a short encounter and will require deicing or even a flight diversion.
Moderate (MOD)
Which layer of the atmosphere contains almost all of the clouds and precipitation?
Troposphere
How would you say FEW000 if there are no remarks?
“Few clouds at less than five zero”
A high pressure system spins in which direction?
Highs spin clockwise
How would you say BKN000 if there are remarks explaining the obscurations?
“Sky partially obscured”
How long are Center Weather Advisories valid for?
2 hours
9900 in an FB indicates the wind is:
Light and variable
What are the 3 stages of a thunderstorm cell?
- Towering cumulus
- Mature (peak intensity)
- Dissipating
WST identifies what?
Convective SIGMET
When temperature is missing, read /11 as ______.
“Temperature missing, dewpoint one-one.”
What is the lowest layer of the atmosphere?
Troposphere
How would you say: “KOKC 011955Z COR….”
“Oklahoma City Airport Corrected one niner five five observation…”
Where will you find convective SIGMETs being issued?
Continental US
A parcel of ______ air expands and cools as pressure decreases with height.
rising
Which product would provide a forecast of freezing levels over New England?
AIRMET ZULU
Any of the forms of water particles that reach the ground is _________.
Precipitation
Turbulence caused by obstructions, such as trees, buildings, mountains, etc… is called ________.
Mechanical Turbulence
What cloud consists of a featureless low layer that can cover sky?
Stratiform
Which weather office provides consultation to ARTCCs?
Center Weather Service Units (CWSUs)
______ is an unscheduled weather advisory issued by CWSU meteorologists for ATC to use to alert pilots of existing or anticipated advises weather within the next 2 hours?
Center Weather Advisory (CWA)
Air flow around a low ______ in a counter-clockwise motion and _______ causing the air to cool and eventually condense into clouds and precipitation.
converges, rises
Which front is associated with poor visibility, smooth air and steady precipitation?
Warm front
Precipitation formation requires water vapor, lift and ______.
Growth
What 3 phases make up a downburst cycle?
Formation
Impact
Dissipation
Which air mass diverges in a clockwise motion and sinks?
A high
A storm produced by cumulonimbus (CB) clouds and always accompanied by lightning and thunder is a ________.
Thunderstorm
A composite of two fronts as a cold front overtakes a warm front or stationary front.
Occluded Front
Jet streams often produce what type of turbulence?
Clean Air Turbulence (CAT)
The interface or transition zone between two air masses of different density
Frontal Zone
_________ is an unscheduled discussion product issued by CWSU meteorologists that summarizes anticipated weather conditions with potential impact on air traffic flow control and flight operations in an ARTCC’s area?
Meteorological Impact Statement (MIS)
A downburst that covers an area of up to 2.5 miles alongside peak winds up to 150 kts and can last from 2-5 minutes is called _______.
A Microburst
VV stands for ______ _______ and indicates what?
VV = Vertical Visibility
Indicates an Indefinite Ceiling
What are the 4 classifications of icing?
Trace (TRACE)
Light (LGT)
Moderate (MOD)
Severe (SEV)
Rain that freezes on contact with the ground is _______.
Freezing Rain (FZRA)
Warm air over a cold surface creates which 3 things?
Smooth air
Poor visibility
Stratiform clouds, fog and drizzle
This type of icing will not require deicing equipment unless this type of icing is encountered for an extended period of time.
Trace (TRACE)
The weather phenomena DU stands for:
Widespread dust
How long are convective SIGMETs valid for?
2 hours
How would you say: “33037G46KT 300V010”
“Wind 330 37 gusts 46. Wind variable between 300 and 010.”
Which precipitation types most commonly produce instrument weather?
Rain
Drizzle
Snow
What are the 2 moisture properties
Continental
Maritime
What are the 3 cloud forms?
Cirriform
Cumuliform
Stratiform
What cloud produces little or no turbulence, but can produce icing?
Stratiform
An RVR proceeded by an “M” (ex R16/M5000FT) means ______.
RVR is “Less than” the number reported
Which body of water is NOT a primary source of water vapor?
The Salt Lake is NOT a primary source
Thunderstorm cell formation requires ______, unstable air, and lift.
Water vapor
Air flow around a high:
Converges or Diverges
diverges
Sinking air _______ and ________.
compresses and warms
______ occurs when the temperature remains below freeing throughout the entire depth of the atmosphere.
Snow (SN)
How would you say R22R/P6000FT ?
“Runway 22R RVR more than 6000.”
Temperature increases with altitude in the _______.
Stratosphere
The weather phenomena GR stands for:
Hail
What is the greatest cause of fatal accidents?
Visual flight into IFR conditions
The weather phenomena FC stands for:
Funnel Cloud (or tornado/waterspout)
Which adverse effect of structural icing is LEAST significant to an aircraft?
Increased drag
or
Increased weight
Increased Weight
The weather phenomena PO stands for:
Well-developed dust/sand whirls
The weather phenomena SS stands for:
Sand Storm
A maximum of atmospheric pressure on a surface weather chart. Also known as an anti-cyclone.
A high
The weather phenomena -FC stands for:
Funnel cloud not touching the ground
The weather phenomena SA stands for:
Sand
TAFs are issued by who?
The NWS
The weather phenomena DS stands for:
Dust Storm
If no temperature or dewpoint is displayed, read it as ______.
“Temperature missing, dewpoint missing.”
How would you say: “…35013G34KT”
“Wind 350 at 13 gusts 34”
A minimum of atmospheric pressure on a surface weather chart. Also known as a cyclone.
A low
What are the requirements to solicit PIREPs?
Ceilings at or below 5,000ft Vis 5mi or less Thunderstorms Turbulence Icing Wind Shear Volcanic Ash Braking Action Advisories
When dewpoint is missing, read 15/ as ______.
“Temperature one-five, dewpoint missing.”
The qualifier PR stands for:
Partial
Relatively strong winds in the upper troposphere are known as the ________.
Jet Stream
What cloud can have tops reaching over 60,000ft?
Cumuliform
What is used in a TAF to show a 30% chance?
PROB30
Which product would be used to firecast an isolated severe thunderstorm 25 miles W of Hill City, KS?
Convective SIGMET
What are the five layers of the earth?
Exosphere Thermosphere Mesosphere Stratosphere Troposphere
Are SIGMETs scheduled or unscheduled?
Unscheduled
The qualifier DR stands for:
Low Drifting
Controllers shall advise pilots of hazardous weather that may impact operations within _____ NM of their sector.
150 NM
The weather phenomena IC stands for:
Ice Crystals
Cold air mass moving over a warm surface often produces (unstable or stable) air.
Unstable air
Cold over Warm = unstable
A front which is stationary or nearly so.
Stationary Front
Liquid water at temperatures below the freezing point and causes instant feezing
Supercooled Water
This type of icing is so quick/intense that deicing equipment fails to reduce the hazard. Immediate flight diversion is necessary.
Severe (SEV)
Change in wind direction of 45 degrees or more in less than 15 minutes, and has sustained winds of 10 kts or more is a ________.
Wind shift
Greatest distance that can be seen throughout at least half of the horizon circle.
Prevailing Visibility
_______ occurs when there is a deep layer aloft with above freezing temperatures and a shallow layer of below freezing air at the surface.
Freezing Rain (FZRA)
Drops freeze on contact with ground or exposed objects
The 3 ingredients for a thunderstorm cell are:
Water vapor
unstable air
lift
A low pressure system spins in which direction?
Lows spin counter-clockwise.
Lows-Left over the top
When the _______ is greater than zero, the air is unsaturated.
Temperature-dew point spread
AIRMET TANGOs are for:
Moderate Turbulence
Winds >30 kts
LLWS
SIGMETs
Convective SIGMETs
AIRMETs
Which are scheduled and which are unscheduled?
SIGMET: Unscheduled
Convective SIGMET: Scheduled
AIRMET: Scheduled
When temperature-dew point spread ________, relative humidity _______.
Temperature-dew point spread DECREASES, Relative humidity INCREASES.
Temp-dew point |v|
Relative humidity |^|
If the wind in an FB is reported at FL300 as 760050, what is the wind and temperature?
260 at 100. Temperature -50
What are the two types of PIREPs?
Urgent (UUA)
Routine (UA)
When the air is too dry for cumuliform clouds to form, _____ currents caused by uneven surface heating can still be active and cause turbulence.
Convective
A front that moves in such a way that colder air replaces warmer air.
Cold Front
The weather phenomena SQ stands for:
Squalls
Which type of air condenses thus forming clouds and precipitation?
Cooling air
What generates turbulence between two wind currents of differing wind directions and/or speeds?
Wind shear
Poor visibility, smooth air and steady precipitation are associated with _____ fronts.
Warm
Cold air over a warm surface creates which 3 things?
Turbulence
Good Visibility
Cumuliform clouds and showers
What is responsible for most weather-related accidents?
Wind
Pressure usually _______ as a front approaches and _______ after it passes.
decreases ; increases
What does DSNT stand for?
Weather beyond 10SM
How would you say: “SPECI KOKC 222108Z…”
“Oklahoma City Airport Special Report, zero eight observation.”
A forecast of non-convective LLWS would be found in what NWS product?
TAF
Which precipitation type occurs when there is a deep layer aloft with above freezing temperatures, with a shallow layer of below freezing air at the surface?
Freezing rain (FZRA)
A warm air mass moving over a cold surface produces (unstable or stable) air.
Stable air
Warm over Cold = stable
