What National Weather Service office provides meteorological forecasts and advise to ARTCC's and other FAA facilities regarding weather impact on their missions?
Center Weather Service Unit (CWSU)
Within which layer of the atmosphere does temperature increase with altitude, making it a stable layer, generally devoid of significant weather?
Precipitation formation requires water vapor, lift, and ________.
a growth process
What type of air mass produces stable air that is associated with smooth air, poor visibility, and stratiform clouds?
A warm air mass moving over a cold surface
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 percent by volume?
Virtually all aircraft fly in which two layers of the atmosphere?
Troposphere and Stratosphere
When the ______ is greater than zero, the air is unsaturated.
temperature-dew point spread
A sinking parcel of air compresses and ________ as it encounters increasing pressure; this causes a cloud to quickly _________.
What type of clouds look like fluffy cotton balls or heaps, indicate upward vertical motion or thermal uplift of air, and can produce severe turbulence, icing, and other hazards?
Air flow around a high diverges in a ________ motion and _______, causing the air to compress and warm, which tends to dissipate clouds.
Standard atmosphere is NOT used for _________.
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 __________.
Which front is associated with poor visibility, smooth air, and steady precipitation?
A warm front
What type of precipitation occurs when there is a shallow layer aloft with above freezing temperatures, with a deep layer of below freezing temperatures based at the surface?
What is a characteristic of a temperature inversion?
Increased temperature with increased altitude
When de-icing or anti-icing equipment fails to reduce or control the icing hazard, the icing is categorized as _________.
A sudden wind shift, even at low speeds, can be hazardous on takeoff and landing because it can __________.
quickly become a crosswind or tailwind
Which airplane type would be most at risk from a 25-knot crosswind on landing?
Small, general aviation, single propeller
Water vapor, lift, and unstable air are necessary for the formation of __________.
A thunder storm cell
Low-level wind shear (LLWS) is a change in wind speed of _______ knots or more within ______-feet AGL.
Airplane performance gradually degrades as the wind ________.
turns perpendicular to the runway
Severe damage can occur if ________ is ingested into an engine.
An area as large as 10 miles or more of strong winds reaching speeds as high as 120 knots, on or near the ground, is a _________.
Which stage of a thunderstorm is characterized by updrafts exceeding 3,000 feet per minute?
What type of turbulence is caused by any obstruction to the wind, such as buildings or mountains?
What type of turbulence causes occupants to be forced violently against seat belts or shoulder straps, unsecured objects to be tossed about, and makes food service and walking impossible?
Which effect occurs to airplanes on departure during a high density altitude condition?
A slower rate of climb
What is NOT true regarding fog?
Fog forms slowly, allowing pilots to avoid the hazard
Light turboprop aircraft are more susceptible to icing than commercial jet aircraft because they typically fly ____________.
at lower altitudes
What are the 5 layers of the Earth's atmosphere?
Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere
The transition boundary between the troposphere and the stratosphere is called the ________.
Relatively strong winds concentrated within a narrow, horizontal band in the upper troposphere is called a _________.
The two jest streams commonly identified are the _________ and the _________.
Polar jet stream, Subtropical jet stream
The jetstreams flow from ______ to ______.
Which layer of the atmosphere contains almost all clouds and precipitation?
What is the value of sea level pressure in the standard atmosphere?
29.92 inches of mercury
What is the raw material for clouds and precipitation?
An air parcel that has the capacity to hold more water vapor is _________.
When the ________ decreases to zero, the air becomes ________, and condensation will form dew, fog, or clouds.
temperature-dew point spread, saturated
What are the four cloud forms?
Stratiform, Cumuliform, Nimboform, and Cirriform
A parcel of ________ air expands and cools as pressure decreases with height.
Which cloud form often produces widespread IFR weather?
What are the charactoristics of cirriform clouds?
High-level clouds which form above 20,000 ft, usually composed of ice crystal but contain no significant icing
What are the charactoristics of nimboform clouds?
Nimbus comes from the Latin word meaning "rain," tytpically forms between 7,000-15,000 ft, brings steady precipitation, can pose a serious icing problem
What are the charactoristics of cumuliform clouds?
Resembles white fluffy cotton balls or heaps, indicates rising air currents and may produce icing, turbulence, and other hazards.
What are the charactoristics of stratiform clouds?
"Stratus" is Latin for "layer" or "blanket," consists of a featureless lower layer that can cover sky, often produces widespread IFR weather, little or no turbulence, but can produce icing
Air flow around a low ________ in a counterclockwise motion and ________, causing the air to cool and eventually condense into clouds and precipitation.
What are the three temperature properties of an air mass?
Artic (A), Polar (P), and Tropical (T)
What are the two moisure properties of an air mass?
Continetal (c), and Maritime (m)
Cold air mass moving over a warm surface often produces unstable air associated with:
Turbulence, good visibility (outside of clouds), and cumuliform clouds and showers.
A warm air mass moving over a cold surface often produces stable air associated with:
Smooth air, poor visibility, stratiform clouds, fog, and drizzle.
_______ is a boundary or transition zone between two air masses of different density, and thus, (usually) of different temperature.
A Maritime Tropical (mT) air mass is ________ and ________.
A ________ air mass moving over a ________ surface often produces unstable air associated with turbulence, good visibility, cumuliform clouds, and showers.
Which front moves in such a way that warmer air replaces colder air?
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?
What NWS entity provides consultation, forecast, and advice to Air Route Traffic Control Centers (ARTCCs) regarding weather impacts?
When an airplane is taking off into a headwind, gusts may cause it to
bounce on the runway
A variable wind can be hazardous on takeoff and landing because it could _______.
quickly become a crosswind or tailwind
Which type of aircraft will perform better in adverse wind conditions, due to its higher takeoff and approach speeds?
Most aircraft accidents related to instrument weather involve pilots who ________.
are not instrument rated
Which precipitation types most commonly produce instrument weather?
Rain, drizzle, and snow
What are the 4 turbulence intensity classifications?
Light, Moderate, Severe, and Extreme
What type of turbulence momentarily causes slight erratic changes in altitude and/or attitude (pitch, roll, yaw)?
During what type of turbulence is the aircraft violently tossed about and practically impossible to control?
When the air is too dry for cumuliform clouds to form, _______ currents called thermals can still be active and cause turbulence.
Which of the following clouds would provide visual proof that a mountain wave exists?
What generates turbulence between two wind currents of differing wind directions and/or speeds?
High density altitude ________ an aircraft's power and thrust.
What are the three types of structural icing?
Rime, Clear, and Mixed
What are the 4 icing intensity classifications?
Trace, Light, Moderate, Severe
Although ________ is the most common type of icing, it is the least serious because it is relatively ineffective in disturbing the airflow and it is easier to remove.
With ________ ice, the rate of accumulation may create a problem if flight is prolonged (over 1 hour). Occasional use of deicing/anti-icing equipment removes/ prevents accumulation.
Aircraft icing potential is NOT dependent upon ________.
Which adverse effect of structural icing is LEAST significant to an aircraft?