Aviation Weather Flashcards
Under which condition does advection fog usually form?
Moist air moving over colder ground or water
Which is a characteristic of LLWS as it relates to frontal activity?
With a warm front, the most critical period is before the front passes the airport
Which weather phenomenon is always associated with the passage of a frontal system?
A wind change
Where can wind shear associated with a thunderstorm be found?
On all sides of the storm and directly under the cell
In which meteorological environment is aircraft structural icing most likely to have the highest rate of accumulation?
Freezing rain
Stability can be determined from which measurement of the atmosphere?
Ambient lapse rate
The tropopause is generally found when the free air temperatures are
between -55C and -65C
The most frequent type of surface based temperature inversion is that produced by
radiation on a clear, relatively still night
The average height of the troposphere in the middle latitudes is
37,000 feet
The strength and location of the jet stream is normally
weaker and farther north in the summer
True Altitude
The aircrafts actual height above sea level
Absolute Altitude
The height of an aircraft above the terrain over which it is flying
Indicated Altitude
The altitude as it is read from the altimeter
Pressure Altitude
The height above a standard datum plane; a theoretical level where the weight of the atmosphere is 29.92” Hg
Density Altitude
Air density given as a height above mean sea level
Stable Air Mass
Stratiform: clouds or fog
Continous precipitation
Smooth air
Fair to poor visibility: smoke or haze
Unstable Air Mass
Cumuliform clouds
Showery precipitation
Rough air
Good visibility
The amount of water vapor that air can hold is largely dependent on
Air temperature
A jet stream is defined as wind of
50 knots or greater
Where do squall lines most often develop?
Ahead of a cold front
Frontal waves normally form on
Slow moving cold fronts or stationary fronts
What is the expected duration of an individual microburst?
Seldom longer than 15 minutes from the time the burst strikes the ground till dissipation
Fair weather cumulus clouds often indicate
Turbulence at and below the cloud level
What type of clouds can be expected when an unstable air mass is forced to ascend a mountain slope?
Clouds with extensive vertical development
