Weather Information Flashcards
Do you have a weather briefing for todays flight? What are some other approved weather sources?
- AWC
- Foreflight
- Briefer
- FSS in plane
- AWOS
What are the standard temperature and pressure values for sea level?
29.92
15°C
What is the flow of a low pressure system? A high pressure system?
- Low Pressure
- Counterclockwise north of the equator
- Clockwise south of the equator - High Pressure
- Clockwise north of the equator
- Counterclockwise south of the equator
Describe the different types of fronts.
- Cold Front: cold air mass pushes into a warmer air mass. Can be twice as fast as a warm front
- Warm Front: warm air mass pushes into a cooler air mass. Move slower than cold because its harder to push through cold fronts
- Stationary Front: when a cold front or warm front quit moving. When two masses are pushing against each other but neither is powerful enough to move the other
- Occluded Front: A warm air mass pushes into a colder air mass and then another cold air mass pushes into the warm air mass.
What is a “trough”? What is a “ridge”?
- Trough: an elongated area of relatively low atmospheric pressure
- Ridge: an elongated area of relatively high pressure extending from the center of a high-pressure region
When temperature and dew point are close together (5 degrees), what type of weather is likely?
Fog
What is the difference between stable and unstable air?
- Stable: When warm air stays above cold air. The weather is likely to remain calm
- Unstable: Happens when there is a quick change in temperature
Name the three types of structural ice that may occur in flight. What is the definition of the term “freezing level” and how can you determine where that level is?
- Clear
- Mixed
- Rime
- Freezing level: the lowest altitude in the atmosphere, over a given location, at which the air temperature is 0°C.
- Subtract 2°C per 1,000’ from 15°C and then add the result to field elevation
What are the three ingredients of a thunderstorm?
- Sufficient water vapor (moisture).
- An unstable temperature lapse rate. Stability is the resistance of the atmosphere to upwards or downwards displacement. An unstable lapse rate allows any air mass displacement to further grow vertically.
- An initial uplifting force (e.g., front passages, orographic lifting by typography, heating from below, etc.).
What are the three stages of a thunderstorm?
- Cumulus (3-5 mile height) – The lifting action of the air begins, growth rate may exceed 3000 fpm.
- Mature (5-10 miles height) – Begins when precipitation starts falling from the cloud base. Updraft at this stage may exceed 6000 fpm. Downdrafts may exceed 2500 fpm. All thunderstorm hazards are at their greatest intensity at the mature stage.
- Dissipating (5-7 miles height) – Characterized by strong downdrafts and the cell dying rapidly.
What is a microburst?
A sudden, powerful, localized air current, especially a downdraft
How often are TAF’s and METAR’s issued
- TAF: 4 times per day every 6 hours
- METAR: Every hour
How far is the radius that a TAF is accurate?
5sm radius
What are “squall line” thunderstorms?
A group of storms arranged in a line, often accompanied by “squalls” of high wind and heavy rain. 10-20 miles wide
Name one type of fog and explain.
- Radiation fog – Occurs on calm, clear nights when the ground cools rapidly due to the release of ground radiation.
- Advection fog – Warm, moist air moves over a cold surface. Winds are required for advection fog to form.
- Ice fog – Forms when the temperature is much below freezing and water vapor turns directly into ice crystals. Ice fog is common in the arctic regions, but also occurs in mid-latitudes.
- Upslope fog – Moist, stable air is forced up a terrain slope and cooled down to its dew point by adiabatic cooling.
- Steam fog – Cold, dry air moves over warm water. Moisture is added to the airmass and steam fog forms.
