CHAPTER 4 Aviation Weather Related To IFR Flying Flashcards
(56 cards)
What causes weather?
Weather is primarily caused by heat exchanges in the atmosphere and the surface due to temperature differences.
What are isobars?
Isobars are lines connecting points of equal pressure.
What do closely spaced isobars indicate?
Strong winds.
What do widely spaced isobars indicate?
Lighter wind on surface charts.
What is the Pressure Gradient Force (PGF)?
The force that causes winds to migrate from high to low pressure areas.
What does the Coriolis force do?
Deflects air to the right in the Northern Hemisphere and left in the Southern Hemisphere.
What is the effect of friction force on wind?
It slows the wind due to obstructions to wind flow.
What is an air mass?
A body of air with uniform moisture and temperature properties.
What is a front?
A boundary or transition zone between two air masses.
What are the four main types of fronts?
- Cold Front
- Warm Front
- Stationary Front
- Occluded Front
What happens when flying across a front?
Pilots will experience a change in winds and usually temperature.
What is a squall line?
Non-frontal lines composed of active, steady-state thunderstorms.
What does lapse rate indicate?
The rate of temperature fluctuation relative to the increase in altitude.
How can a pilot use the ambient lapse rate?
To measure air stability.
What is the average dry adiabatic lapse rate?
About 3°C for every 1,000 feet gained of altitude.
What are the three ingredients required for precipitation?
- Water vapor
- Sufficient lift
- Growth process for droplets
How is cloud formation determined?
By the stability of the air.
What are the different types of clouds based on height?
- Low clouds: Surface - 6,500 feet
- Middle clouds: 6,500 - 13,000 feet
- High clouds: 10,000 - 25,000 feet
Which cloud formation is characteristic of turbulence?
Cumulus clouds.
What are Altocumulus Standing Lenticular clouds (ACSL)?
Clouds that extend downwind of a mountain and indicate very strong turbulence.
Which clouds contribute to structural icing?
Low clouds.
Under what conditions does structural icing develop?
In the presence of large supercooled water droplets, moisture, and high humidity.
What are the three types of structural icing?
- Rime
- Clear
- Mixed
What is freezing rain?
Precipitation that instantly freezes into ice upon impact.