Meteorology Flashcards
What is the weather like as a cold front passes?
- Winds: Gusting and veering
- Temperature: Sudden drop
- Pressure: Sharp rise
- Clouds: Cb
- Precipitation: Formed by warm air expanding as it is lifted by advancing cold air. Heavy rain, thunder and lightning, may hail.
- Visibility: Poor but improving
- Dew point: Sharp drop
What is the weather like before a cold front passage?
- Winds: South to Southwest
- Temperature: Warm
- Pressure: Falling Steadily
- Clouds: Increasing: Cu, TCu and Cb
- Precipitation: Short period of showers
- Visibility: Fair to Poor in Haze
- Dew Point: High; remains steady
What is the weather like after a cold front passage?
- Winds: West to Northwest
- Temperature: Steadily dropping
- Pressure: Rising Steadily
- Clouds: Cu
- Precipitation: Showers then clearing
- Visibility: Good, except in showers
- Dew point: Lowering
Surface pressure patterns such as those represented on surface analysis charts, can be considered as representative of the atmosphere up to what altitude?
Surface pressure patterns can be considered representative of the atmosphere up to an altitude of 3,000 feet AGL.
How often are surface analysis charts issued?
Surface analysis charts are issued four times a day at six-hour intervals.
What would the designation UACN10 indicate?
A regular priority PIREP.
What would the designation UACN01 imply?
An urgent priority PIREP.
What would be the internal and external reaction to Light intensity turbulence?
Aircraft Reaction: Slight erratic changes (turbulence), Slight rhythmic changes (chop)
Inside Aircraft: Slight strain against seat belts, little or no difficulty walking
What would be the internal and external reaction to Moderate intensity turbulence?
Aircraft Reaction: Changes to altitude/attitude but aircraft remains in control, rapid bumps or jolts (Chop)
Inside Aircraft: Definite strain against seat belts, objects are dislodged, difficulty walking
What would be the internal and external reaction to Severe intensity turbulence?
Aircraft Reaction: Large, abrupt changes in altitude/attitude and airspeed, momentarily out of control
Inside Aircraft: Forced violently against seat belts, walking is impossible, unsecured objects thrown about
How often are GFA charts issued and how long are they valid for?
Graphic Area Forecast charts are issued four times daily at 00Z, 06Z, 12Z and18Z. They are valid for 12 hours with an additional 12-hour IFR outlook.
How many regions are covered by GFA’s?
There are seven regional charts that are issued: GFACN31-Pacific GFACN32-Prairies GFACN33-Ont/Que GFACN34-Atlantic GFACN35-Yukon GFACN36-Nunavut GFACN37-Arctic
What information is presented and included in a GFA?
Forecast depiction of weather conditions below 24,000 ft; consists of three Cloud & Weather charts and three Icing, Turbulence & Freezing Level charts.
What meteorological factors are necessary for the creation of thunderstorms?
Unstable air, moisture and a lifting force.
What are the three stages to a thunderstorm?
Cumulus stage (building), mature stage and dissipating stage.
What makes up the composition of the atmosphere?
Nitrogen comprises 78%; oxygen about 28%; and other gases about 1%. The other 1% consists of gases such as argon, carbon dioxide, neon, helium and more. When water vapour is added, the percentages decrease proportionately.
Does the height of the troposphere change throughout the year?
Yes, the height of the troposphere changes with latitude and the seasons. It is higher in summer than in winter.
What is the term used to describe when a liquid changes to a gas?
Evaporation
What is the term used to describe when a gas changes to a liquid?
Condensation
What is the term used to describe when a liquid changes to a solid?
Freezing
What is the term used to describe when a solid changes to a liquid?
Melting
What is the term used to describe when a solid changes to a gas?
Sublimation
What is the term used to describe when a gas changes to a solid?
Sublimation
What is dew point?
The “dew point” is the temperature at a given pressure, to which the air must be cooled to cause saturation.
If the cloud type does not have a prefix (such as, Alto or Cirrus) then it’s cloud base can be expected at approximately what altitude(s)?
If there is no prefix, then the cloud base can be expected at approximately 6,000’ or less of altitude.
Where can the cloud base be expected for Alto clouds?
The base of clouds with the alto prefix can be expected anywhere from 6,000-20,000’.
Where can the cloud base be expected for Cirrus clouds?
The base of clouds with the Cirrus prefix can be expected anywhere from 18,000-45,000’.
What is the ICAO standard lapse rate?
1.98 degrees per 1000 feet
What is the lapse rate for a saturated air mass? (Wet rate)
1.5 degrees per 1000 feet
What is the lapse rate for a dry air mass? (Dry rate)
3 degrees per 1000 feet
What characterizes fractus clouds?
Windy conditions and torn, broken clouds.
What characterizes nimbus clouds?
Precipitation forms in nimbus clouds.
What are the characteristics of unstable air?
Good visibility, gusty winds, clouds of vertical development (cumulus), showery precipitation, turbulent conditions.
What are the characteristics of stable air?
Poor visibility, stratus clouds, low or steady winds, steady precipitation or drizzle.
What are the characteristics of cumulus clouds?
Puffy cotton-ball type clouds of vertical development. Forms in unstable air in rising air currents.
What are the characteristics of stratus clouds?
Flat clouds of horizontal development. Forms in layers with a large span, and is indicative of stable air and poor visibility.
What are the characteristics of cirrus clouds?
High-level thin and wispy forming clouds composed of ice crystals.
What is diurnal variation?
Diurnal variation is where the air close to the surface of earth is colder at night than during the day. This is caused by the sun’s rays no longer being absorbed by the surface of the earth during the night.
What kinds of lifting forces may help create a thunderstorm?
Frontal lift, convergence, convection, etc…
What is Relative Humidity?
Relative Humidity is the amount of moisture contained within a parcel of air and is expressed as a percentage.
What is Wind Shear?
Wind shear is a sudden change in wind direction or velocity.
What effect can wind shear have on an aircraft?
Wind shear can cause an aircraft to increase/decrease airspeed, increase climb-rate or rate of descent, and cause the aircraft to yaw suddenly.
What are the characteristics of towering cumulus clouds?
Towering cumulus clouds are clouds of vertical development and are indicative of unstable air and turbulent conditions.
