Weather Flashcards
What is the standard lapse rate?
2 degree loss per 1000ft altitude gain
What indicates more stable air when comparing lapse rates?
If the lapse rate is less than the standard lapse rate
What indicates unstable air when comparing lapse rates?
If the lapse rate is more than the standard lapse rate
What are the characteristics of unstable air?
- Cumuliform Clouds
- Showery precipitation
- Turbulence
- Good visibility
What are the characteristics of stable air?
- Stratiform Clouds/Fog
- Continuous precipitation
- Smooth air
- Poor visibility
What type of air is more stable and resists vertical movement?
Cool dry air
What type of air is more unstable?
Moist warm air
What is an exception to the instability of moist warm air?
Temperature inversion
Fill in the blank: If the lapse rate is less than 2 degrees per 1000ft, the air is _______.
more stable
Fill in the blank: If the lapse rate is greater than 2 degrees per 1000ft, the air is _______.
unstable
Which is more dense: dry air or humid air?
Dry air is more dense than humid air
What does relative humidity measure?
Relative humidity measures the percent of water vapor held vs. how much is possible
How does temperature affect relative humidity?
Higher temps have lower relative humidity with the same amount of water vapor
How much does the possible water vapor held change with temperature?
Possible water vapor held doubles every 20°F
What is dewpoint?
Dewpoint is the temperature where the air can’t hold any more moisture
What are the three classifications of clouds based on altitude?
Low: Surface to 6500 ft AGL
Middle: 6500 - 20000 ft AGL
High: 20000 ft AGL and above
AGL stands for Above Ground Level.
Which clouds are classified as low altitude clouds?
Stratus, Stratocumulus, Nimbostratus
These clouds are typically found at lower altitudes.
Which clouds are classified as middle altitude clouds?
Altostratus, Altocumulus
These clouds are found between 6500 and 20000 ft AGL.
What are the high altitude clouds?
Cirrostratus, Cirrocumulus, Cirrus
These clouds are generally above 20000 ft AGL.
What is fog?
A cloud on the surface to 50 ft AGL
Fog significantly reduces visibility.
What is radiation fog?
Fog that forms when the ground cools rapidly and air temperature reaches the dew point
This type of fog typically occurs during the night or early morning.
What is advection fog?
Fog that forms when warm air moves over a cold surface, requiring wind
Commonly found in coastal areas.
What is upslope fog?
Fog formed when moist air is forced up land features, requiring wind
This type of fog is often seen in mountainous regions.
What is steam fog?
Fog that occurs when cold air moves over warm water
This type of fog can often be seen over lakes or rivers.
What is ice fog?
Fog formed when water vapor rapidly turns into ice crystals
Typically occurs in extremely cold temperatures.
What is precipitation?
Any water particles falling to the ground
This includes rain, snow, sleet, and hail.