Aviation Weather Basics

What is a microburst?

• A large-scale wind pattern that lasts for several days

• A sudden, powerful, localized air current, especially a downdraft

• A gentle and steady breeze that affects local weather conditions

• A rapid upward movement of air used to gain altitude in gliding

What characterizes a stable air mass?

• It tends to resist vertical movement.

• It encourages strong vertical air currents.

• It is associated with clear skies and calm weather.

• It often leads to the rapid development of thunderstorms.

What is an unstable air mass?

• Air that remains stationary regardless of external forces

• Air that easily mixes with surrounding air masses, creating a uniform temperature

• Air that tends to rise and form precipitation

• Air that suppresses cloud formation and maintains dry conditions

Which condition is most conducive to the formation of radiation fog?

• Warm, moist air over a cold surface

• Cold air moving over a warm, wet surface

• Clear skies and calm winds at night

• High humidity and strong winds

What causes advection fog to form?

• Warm air rising over a mountain

• Cold air settling over a warm surface

• Warm, moist air moving over a cooler surface

• Rapid cooling of the earth's surface under clear skies

How does upslope fog form?

• When warm, moist air cools as it rises along a slope

• From the evaporation of water into cold air

• When cold air descends a slope, warming adiabatically

• Through the mixing of two air masses of different temperatures

What is steam fog?

• Fog that forms when cold air moves over warm water

• Fog that appears over land when there is a sudden drop in temperature

• A type of fog that forms in valleys during the winter

• Fog that is composed entirely of ice crystals

What is ice fog?

• Fog made of water droplets that freeze upon contact with surfaces

• Fog that forms exclusively over ice-covered bodies of water

• Fog composed of tiny ice crystals, occurring under very cold conditions

• A dense fog that precedes snowfall

What are the stages of thunderstorm development?

• Cumulus, Mature, Dissipating

• Formation, Expansion, Contraction

• Initial, Growth, Decay

• Developing, Peaking, Waning

What is an occluded front?

• A front where a cold air mass overtakes a warm air mass

• The boundary where two similar air masses meet but do not mix

• A front where a warm air mass overtakes a cold air mass

• The zone where an air mass becomes stationary