What is the importance of dew point?
Dew point is the temperature at which the water vapor will start to condense. When the temperature is the dew point, the air becomes saturated with water. The closer you are to dew point, the foggier it will be.
For each 1,000ft higher in the troposphere, what happens to each of the 3 temperatures?
The standard temperature decreases by 2C
The unsaturated air temperature air temperature decreases by 3C
The dew point increases by 1/2C
how do you calculate the cloud base?
subtract the dew point from the temperature, divide by 2.5 and time 1000ft
What is stable and unstable air and how does it affect clouds?
Stable air: little or no temeprature decrease with altitude
Cloud types: Stratus (look layered)
Unstable air: much cooler above than down below
Cloud types: Cumulus (fluffy and bumpy),
What does the orefic nimbo or suffic nimbus mean?
rain cloud
What are the four families of clouds?
- High clouds: Found between 16,500 and 45,000ft. Called cirriform clouds. Include cirrus, cirrocumulus, and cirrostratus
- Middle Clouds: 6500-23000ft. Include altostratus, and altocumulus
- Low clouds: surface to 6500ft. Incluse stratus, stratocumulus, and fair weather cumulus
- Clouds with extensive vertical development: may extend from 1000 to as high as 60000. Includes cumulus and cumuonumbis(thunderstorms)
What are some characteristics of smooth air?
What are some characteristics of unstable air?
What is the lapse rate? what does it affect?
Lapse rate referse to the decrease of air temperature will altitude. It measures the resistance to vertical displacement of an air mass. The standard lapse rate is 2C per 1000ft.
if the lapse rate is more than 2, it is unstable, and if it is less than 2 it is stable
When are thunderstorms created?
When air has sufficient water vapor, and air is forced to rise (due to terrain or unstable air)
Visibilllity can often be worse in stable air. True or False.
True
What is the difference between a POH and a PIM?
A POH is an FAA required document specific to an airplane serial number that tells pilots how to fly and maintain the aircraft, while the Pilot’s Information Manual is not FAA-approved and not specific to the serial number, but tells pilots aircraft information.
What is the difference between boldface and non-boldface items in the emergency procedures section?
Boldface procedeures should be momorized, non-boldface is exra information
What is a weather front
A boundary between two air masses that have different temperatures and humidities.
What does the formation of a thunderstorm require?
A lifting force: upslope wind, weather front, thermals from ground heating
Unstable air, which allows air to continuilly rise and cool
Moist or high-humidity air
What are the stages of a thunderstorm?
Cumulus phase: Vertical cloud buildup with very strong updrafts
Mature stage:
* Has downdrafts reaching 2500 fpm. Precipitation is falling from the cloud base, there are strong, gust surface winds, a sharp temeprature drop, a rapid rise in pressure.
* Has updrafts as much as 6000 fpm causing vertical wind shears as you transfer between updrafts and downdrafts
* Contains most danger
* Can form Cumulonibus Mammatus clouds, which are clouds where the base is a pattern of lumpy pouches. These are associated with the most violent thunderstorms and often tornados
Dissapating stage:
* Mostly downdrafts
* Still dangerous, which possibilities of hail and turbulence
* Ends when there is no rain and downdrafts
Types of Thunderstorms
- Air mass thunderstorms: Associated with an area of convective lifting. Caused by surface heating and last between 20 minutes and 1.5 hours. Their lifespan is limited because they cool the surface during the mature phase, inhibiting updrafts
- Frontal Thunderstorms: Steady state thunderstorms associated with fronts. These thunderstorms last many hours since precipitation falls outside the updraft area.
- Squall line thunderstorms are a narrow band of thunderstorms associated with a cold front.
What is a front?
A front is a boundary between two airmasses of differing temperatures and humidities?
What is the temperature and humidity of high pressure and low pressure air?
High pressure, cold, dry air
Low pressure, warm, humid
What are high pressure and low pressure zones? What kinds of sky conditions do each have?
High pressure zones are where air is descending, and low pressure zones are where air is rising. High pressure zones generally have clear skies, fair weather, and calm air. Low pressure zones have unstable air, cloudy skies, and precipitation.
What are warm and cold fronts and their differences?
Warm fronts are when the warm air mass is moving, and cold fronts are when the cold air mass is moving. Warm fronts move at 10-25 mph. Warm fronts usually have stratiform and cirriform clouds. They have poor visibility, and low to moderate rain. Cold fronts move at 25-30 mph, have cumulus and cumulonibus clouds. There are sometimes thunderstorms.
How do you read surface wind charts?
- Flags point in the direction of the wind
- Short bar = 5
- Long bar = 10
- Flag = 50
What are clouds?
Clouds are a mix of solid ice crystals, liquid water molecules, and air molecules. The ice crystals and water molecules are suspended in the air.
What clouds are forecasted in TAFs?
Cumulonibus only
