23 Fundamentals Of Weather And Aviation Weather Services Flashcards
A cloud of gas and suspended solids extending from the earth surface out many thousands of miles. Always held by the earths gravitational pull.
The atmosphere
Atmosphere is the ______ we live in
Protective bubble
What are the five layers of the earths atmosphere. In order.
Troposphere, stratosphere, mesosphere, thermosphere, exosphere
Which atmosphere?
Contains almost all clouds and precipitation, air pressure and density decreases with altitude, temperature generally decreases with altitude, average vertical depth is 36,000 feet.
Troposphere
What is the transition boundary between the troposphere and the stratosphere?
Tropopause
What atmosphere?
Extends from the tropopause up to 31 miles above the earth’s surface, temperature increases with altitude, stable layer generally devoid of significant weather.
Stratosphere
An increase in temperature with altitude is ab normal and is defined as _____.
Inversion
Hypothetical vertical distribution of the atmospheric temperature, pressure, and density, which by international agreement is considered to be a representative of the atmosphere for pressure altimeter calibration and other purposes, 29.92 inches of mercury
Standard atmosphere
What is standard atmosphere used for?
Pressure altimeter calibrations,
aircraft performance calculations,
aircraft design,
weather related processes
What is the temperature at sea level in Celsius and Fahrenheit?
15°C 59°F
Relatively strong winds concentrated within a narrow horizontal band in the upper troposphere
Jet stream
What are the two jet streams?
Polar and subtropical jet stream
Where is the polar jetstream and the subtropical jetstream located?
The polar jetstream – 30° and 60° latitude,
subtropical jetstream – 20° and 40° latitude
The jet stream flows from _______but the flow often shifts to the ________ due to weather systems and seasonal changes
West to east, north and south
When are jetstream the strongest?
During winter
Jet streams often produced what?
Clear air turbulence – CAT
True or false
Jet streams make air traffic control separation more difficult
True
Why do jet streams make air traffic control separation more difficult?
They cause aircraft to move at different ground speeds
Which layer of the atmosphere contains almost all clouds and precipitation?
Troposphere
Which layer of the atmosphere is stable and generally devoid of significant weather?
Stratosphere
What is the value of sea level pressure in the standard atmosphere?
29.92 inches of mercury
Which two jet streams are commonly identified?
Polar and subtropical
Water in the invisible gaseous form
Water vapor
The change of liquid water into water vapor
Evaporation
The change of ice to water vapor
Sublimation
What is the raw material for clouds and precipitation?
Water vapor
Water vapor constitutes only a _____ percentage of the atmosphere, varies widely in time and space from trace amounts to _____% by volume, approximately half is found below ______ AGL
Small, 4%, 6500
Measure of the hotness or coldness of the air
Temperature
______Air can hold more water vapor than _____air
-cold/warm-
Warm air, cold air
The maximum possible quantity of water vapor that a personal air can hold at any given temperature and pressure
Saturation
What is the difference between saturated and unsaturated?
Saturated – air parcel contains all the water vapor it can hold
Unsaturated – it has the capacity to hold more
The temperature to which a given parcel of air must be cooled at constant pressure and constant water vapor content in order for saturation to occur
Dewpoint
The ratio, usually expressed as a percentage of water vapor actually in the air compared to the amount of water vapor the air could hold at a particular temperature and pressure
Relative humidity
Relative humidity does not indicate the actual water vapor content of the air, but rather how close the air is to ______.
Saturation
Dewpoint is measured in _____
relative humidity is _____
Temperature, ratio
The difference between air temperature and dewpoint temperature is popularly called the_____.
Spread
When the temperature dewpoint spread decreases, relative humidity ______.
Increases
When the temperature dew pointspread decreases to 0, the air becomes _______, and condensation will form_____.
Saturated, dew or fog
A change of water vapor to liquid water
Condensation
A parcel of air that has the capacity to hold more water vapor is ______.
Unsaturated
When the _______decreases to zero, the air becomes ______,and condensation will form dew, fog, or clouds
Temperature dew point spread, saturated
Visible mass of tiny water droplets and or ice particles in the atmosphere above the earth surface
Cloud
What forms when air is cooled to its dewpoint and become saturated?
Clouds form
A parcel of ______ warms as it encounters increasing pressure and is compressed
Sinking air
A cloud will quickly dissipate due to ______
Sinking air
A parcel of sinking air – temperature dewpoint spread _______.
A parcel of rising air – temperature dew point spread_____.
Increases – decreases
Name this cloud
High-level clouds which form above 2000 feet, usually composed of ice crystals, typically thin and white in the appearance, contains no significant icing
Cirriform
cloud
Name this cloud
White fluffy cotton balls or heaps, indicates upward vertical motion or thermal uplift of air, tops can reach over 60,000 feet, they produce icing, turbulence, and other hazards
Cumuliform
Name this cloud
Latin for layer or blanket, featureless low layer that can cover the sky, often produces widespread IFR weather, little or no turbulence, that can produce icing
Stratiform
What is the prefix nimbo I’m o or suffix nimbus mean?
Raincloud
A parcel of ______air expands and cools as pressure decreases with height
Rising air
Which cloud form often produces widespread IFR weather
Stratiform
Air in motion relative to the surface of the earth
Wind
A maximum of atmospheric pressure on the surface weather chart; also known as an anti-cyclone
High
A minimum of atmospheric pressure on a surface weather chart; also known as a cyclone
Low
Airflow around a ______ diverges in a clockwise motion and sinks
High
Airflow around a _______ converges in a counterclockwise motion and rises
Low
High-
Sinking air _____and _____
Compresses and warms
Low -
Rising air ______&_______
Expands and cools
Airflow around a low _____in a counterclockwise motion and _____ causing the air to cool and eventually condense into clouds and precipitation
Converges, rises
A large body of air that has similar horizontal temperature and moisture characteristics
Air mass
Region where air masses originate in acquire their properties of temperature and moisture
Air mass source region
Air masses are classified according to ____&____properties of their source regions
Temperature and moisture
Name the three temperature properties
Arctic – a
polar – P
tropical – T
Name the two moisture properties
Continental – C
maritime – M
Which temperature property?
An extremely deep cold air mass which develops mostly in winter over arctic surfaces of ice and snow
Arctic – A
Which temperature property?
A relatively shallow cool to cold air mass which develops over high latitudes
Polar – P
Which temperature property?
A warm to hot air mass which develops over low latitudes
Tropical – T
Which moisture property is this
- A dry air mass which develops over land
- A moist air mass which develops over water
Continental C
Maritime M
Name the five air masses that can be identified on the air mass source regions chart
Continental arctic – CA -Cold, dry continental polar – CP -Cold, dry continental tropical – CT -Hot, dry maritime polar – MP -cool, moist maritime tropical – MT-warm, moist
-
-
Unstable air
-turbulence
– good visibility outside of Cloud
– cumuliform clouds and showers
-
-
Stable air
-smooth and air
– poor visibility
– stratiform clouds, thought, drizzle
A friend that moves in such a way that colder air replaces warmer air
What color?
Cold front
Blue
A front that moves in such a way that warmer air replaces colder air
What color?
Warm front
Red
A boundary or transition zone between two air masses of different density, usually different temperature
Front
A front which is stationary or nearly so
What color?
Stationary front
Blue/red
A composite of two fronts as a cold front overtakes a warm front or stationary front
What color?
Occluded front
Pink
Which front has a steep slope and air is forced upward abruptly.
Cold front
Which front typically has a gentle slope so the air rising along the front wall surface is gradual
Warm
Which front?
- narrow band of cumulus clouds, showers and thunderstorms along or just ahead of the front if the rising air is unstable
- good visibility and turbulence
Cold front
Which front?
Favors the development of widespread layered or stratiform cloudiness and participation along and a head of the front if the rising air is stable
-Poor visibility, smooth and air and steady precipitation
Warm front
Which front typically moves faster than the other so in time they “catch up”
Cold front moves faster than warm front
Which front?
Cold air undercuts the retreating cold air mass associated with the warm front, further lifting that already rising warm air
-combining the effects of both cold and warm front, clouds and precipitation can occur
Occluded front
Which front?
Boundary between two different air masses, neither of which is strong enough to replace the other
-why variety of weather can be found along this front, usually clouds and prolonged precipitation
A stationary front
A maritime tropical air mass is ____and____
Warm, moist
A______ air mass moving over a _______surface often produces unstable air associated with turbulence, good visibility, cumuliform clouds, and showers
Cold, warm
Which front moves in such a way that warmer air replaces colder air?
Warm front
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
Any of the forms of water particles, whether liquid or solid, that fall from the atmosphere and reach the ground
Precipitation
Precipitation formation requires what three ingredients?
Water vapor, lift, growth process
What are the primary sources in the US water vapor? (4)
Atlantic and Pacific oceans, Gulf of Mexico, the Great Lakes
What transports this water vapor in land?
From ocean
Winds
The _______ of temperature will often determine the type of precipitation that occurs at the surface
Vertical distribution
Precipitation of snow crystals, mostly branched in the form of a six pointed star
Snow
What occurs when the temperature is below freezing throughout the entire depth of atmosphere
Snow
What occurs when there is a shallot layer a loft with above freezing temperatures with a deep layer of below freezing air base at the surface?
Ice pellets
What occurs when there is a D player a loft with above freezing temperatures, with a shallow layer of below freezing air at the surface
Freezing rain
What occurs when there is a deeper layer of above freezing air based at the surface
Rain
Who issues several aviation weather products such as airmets, sigmets, convective sigmets, TAF
NWS offices
How many weather forecast offices are across United States?
122
Center weather service units (CWSU) provide advice and other FAA facilities regarding weather impact on their:
(3)
Missions, equipment outages and repairs, staffing
-
Center weather advisories – CWA meteorological impact statements – MIS
What NWS entity provides consultation, forecast, and advice to air in route traffic control centers regarding weather impacts?
Center weather service unit(CWSU)
