Meteorology Flashcards
What is a front?
The boundary between 2 air masses.
What is a cold front and what kind of weather might you expect?
A boundary separating a mass of cold air from a warmer air mass, resulting in strong winds, precipitation, and temperature drops.
What kind of weather is typically associated with cold fronts?
- Thunderstorms
- Rain showers
- Hail
- Tornadoes
What is a warm front and what kind of weather might you expect?
A transition zone where a warm air mass replaces a cooler air mass, producing gradual changes in weather conditions.
What kind of weather is typically associated with warm fronts?
- Steady precipitation
- Rain
- Snow
- Stratiform clouds
What is an occluded front?
Occurs when a fast-moving cold front overtakes a slower-moving warm front, creating a mix of weather characteristics.
What is a stationary front?
Occurs when two air masses meet but neither is strong enough to displace the other, leading to prolonged cloudy and unsettled weather.
What is a dry line?
A boundary separating a warm, dry air mass from a warm, moist air mass, often triggering thunderstorms.
What is a TROF?
Trough – an elongated line of low pressure.
What is a RIDGE?
An elongated area of high pressure.
What does ISA mean?
International Standard Atmosphere.
What is the standard temperature at sea level according to ISA?
15 C.
What is the standard pressure according to ISA?
29.92 Hg, 1013.2 mb.
What is the standard temperature lapse rate?
-2 degrees/ 1,000 feet elevation gain.
What is RVR?
Runway Visual Range, used when visibility is 1/2 mile or less.
What is an isobar?
An equal line of pressure.
What does closely spaced isobars indicate?
A tight pressure gradient causing high and gusting winds.
What is an isotherm?
An equal line of temperature.
What is an isotach?
An equal line of wind speed.
What is the primary cause of weather on Earth?
The uneven heating of the atmosphere by the Sun.
What is the Coriolis effect?
A phenomenon causing moving objects to appear to curve due to Earth’s rotation.
What is High Pressure in terms of weather?
An area of relatively higher atmospheric pressure at the Earth’s surface.
What weather conditions are associated with high pressure?
- Clear skies
- Light winds
- Dry weather
What is low pressure in terms of weather?
An area of relatively lower atmospheric pressure at the Earth’s surface.
What weather conditions are associated with low pressure?
- Cloudiness
- Rain
- Thunderstorms
What part of the atmosphere does most weather occur?
Within the troposphere.
Where is the Earth’s atmosphere thickest?
Near the equator.
What is the Jet Stream?
A narrow, fast-moving stream of air with wind speeds reaching 50 knots or more.
Where is the jet stream typically found?
In breaks in the tropopause.
What is considered stable air?
Air that resists vertical movement and suppresses cloud formation.
What happens when air rises?
It expands due to the decrease in air pressure.
What is a temperature inversion?
A rise in temperature as altitude increases, contrary to normal conditions.
How many types of fog are there and what are their characteristics?
- Radiation: Forms when the ground cools rapidly at night.
- Advection: Occurs when warm, moist air moves over a colder surface.
- Upslope: Forms when moist air is forced to rise up sloping terrain.
How thick must a cloud be for precipitation to form?
4,000 ft.
What are the 3 ingredients of a thunderstorm?
- Uplifting action
- Unstable air
- Moisture
What are the 3 stages of a thunderstorm?
- Cumulus
- Mature
- Dissipating
What are the 2 types of thunderstorms?
- Air Mass
- Steady State
What kind of clouds characterize a thunderstorm?
Cumulonimbus.
What is a squall line?
A line of severe thunderstorms that form along or ahead of a cold front.
What are embedded thunderstorms?
Individual thunderstorms within a larger area of widespread precipitation.
What is windshear?
A sudden change in wind speed or direction over a short distance.
Where are the three most common locations you might find windshear?
- Thunderstorms
- Jet streams
- Temperature inversions
What is a microburst?
A strong sudden downdraft reaching up to 6,000 ft per minute.
What is a squall?
A sudden, brief burst of strong wind accompanied by rain or snow.
Can you ever dispatch a flight into icing?
Yes, but never Severe.
What conditions must exist to form ice?
Temperatures below 10C and visible moisture.
What are the three types of icing and their characteristics?
- Clear: Forms from supercooled droplets freezing on impact.
- Rime: Forms when supercooled droplets freeze rapidly.
- Mixed: A combination of clear and rime ice.
What is CAT?
Clear Air Turbulence, occurring in cloudless skies, often at high altitudes.
What is a Hurricane?
A powerful tropical storm with strong winds and heavy rain, forming over warm ocean waters.
What is EWINS?
An Enhanced Weather Information System used to collect and share aviation weather data.
What is a SIGMET?
A weather advisory for significant weather phenomena affecting aviation safety.
What is an AIRMET?
A weather advisory alerting pilots to potentially hazardous weather for small aircraft.
