Flashcards in PPL - meteorology Deck (70):
What is relative humidity?
Percentage of how much moisture is in the air
100% is saturation point
What is the dew point?
Temperature that the air needs to cool to to become 100% saturated
What is the layer of atmosphere that general aviators most commonly fly in?
Where is the height of the tropopause the greatest?
What is the standard lapse rate?
1.98°C per 1000 ft
What happens to the lapse rate during an inversion?
It turns negative
What is the dry adiabatic lapse rate and the wet rate usually?
3°C per 1000 ft for dry, and 1.5°C per 1000 ft for wet
What is the lapse rate for a stable atmosphere?
A shallow or negative lapse rate
What is the international standard atmosphere and values?
It is the set of atmospheric conditions in which the world follows as the standard. The values are:
Temperature at sea level: 15°C
Environmental lapse rate: 2°C/1000’
Pressure at sea level: 29.92” Hg
Can air hold more water if the temperature is hot, or cold?
vertical movement of air
Horizontal movement of air
when a solid changes directly to a gas
When gas changes directly to a solid
Lines of differing pressure
Lines of wind velocity
In the N. Hemisphere, which way does the coriolis force deflect the air?
to the right
What altitude and below, does the friction force affect wind?
below 3,000’ AGL
In N. Hemisphere, the air revolves around a high pressure counterclockwise, or clockwise?
Low pressures are know for what type of weather?
Precipitation and ascending air
With increasing altitude does wind tend to veer, or back?
Relatively speaking, if the isobars are very far away, will the wind velocity be fast or slow?
If one stands with their back to the wind in the northern hemisphere, where is the high pressure?
in front and to the right
What is a rapid increase in wind speed lasting for 60 seconds or longer before returning to normal speed?
What is the term for when the wind direction is decreasing?
What is the wind direction if you are heading directly into th e wind, and your heading is 276?
What is the term for when a cloud forms as the result of air moving over a colder surface?
If a cloud has nimbo in the name, what does it mean?
It will produce precipitation
Mist visibility is 5/8 nm or greater while FOG vis. Is ______ than 5/8 nm
The lowest broken or overcast layer of cloud is called?
If the temperature is 15°C, and the dew point is 5°C and the rest follows standard atmospheric conditions, what is the ceiling?
Air being warmed on the side of a mountain rises. These winds are called?
The opposite of anabatic winds are?
Katabatic winds, which is when the air is cooled on the side of a mountain descendsn
During a sunny day, what winds are being produced on the coast of an ocean, and where are they heading in relative to the ocean and land.
A sea breeze, that heads towards land
What precipitation is the windward side of a mountain seeing and what is the leeward side seeing during a Chinook?
Windward side receives precip,
leeward side is dry
What clouds form when stable air containing moisture is blown towards a mountain, and on the leeward side becomes compressed than bounces back up in an oscillating motion?
Cap clouds, lenticular clouds, and rotors
What dangerous type of draft is produced as a result of mountain waves?
When, where, and how for radiation fog
Nighttime before dawn
On the surface
With less than 5 kts of wind, air glides over the ground and becomes cooled until it condenses
Where, when and how for Advection fog
From warm surface to cold
When warm air is blown over a cool surface which absorbs warmth and the air reaches its dew point
When, where, how for Frontal fog
At a front, near the surface
The warm air is above the cold and condenses, the precipitation is cooled further and evaporates in the cold air and re condensates, if this is close to the surface fog occurs
When, where, and how for Arctic Sea Smoke?
Over the sea
The warm water evaporates than saturates the cold air above raising the dew point to meet the air temperature
When, where, how for upslope fog?
On mountain sides
When moist air is forced to rise up the side of a mountain and when it reaches cooler air, it condenses
List the 4 air masses most commonly found over Canada
Maritime tropical – mT
Maritime Polar – mP
Maritime Arctic – mA
Continental Arctic – cA
What is the boundary between two air masses called?
For a Cold Front, what is temperature doing?
For a cold front, what is the dew point doing?
For a cold front, what is the Pressure doing?
While the front is approaching pressures decreases, then increases after
For a cold front, what is the wind doing?
Veering and increasing
For a cold front, what are the clouds doing?
Cirrostratus clouds that change to cumulus, then maybe nimboculumus, it will leave cumulus after passage
For a cold front, what is the precipitation like?
Preceded by showers, than heavy precipitation, after it passes it is showery than clear. This is all depended on stability and temperature in the warm air mass
For a cold front, what is the visibility like?
Bad during precip, then very good after the passage
For a warm front, what is the temperature doing?
For a warm front, what is the dew point doing?
For a warm front, what is the Pressure doing?
While it’s approaching its gonna decrease, then increase after, then usually decrease again
For a warm front, what is the wind doing?
Veering, but less so than with a cold front
For a warm front, what are clouds doing?
Cirrus and cirrostratus, then slowly lowering clouds with possible precip
For a warm front, what is the precip doing?
Showers usually precede the warm front, then drizze and finally after full passage its clear
For a warm front, what is the visibility like?
bad during precip, and hazy behind the front
What is the weather phenomenon when a cold front catches up to a warm front and the resulting weather is a combination between warm front clouds and cold front clouds?
Describe developing, mature, and dissipating stages of a Thunderstorm
· Developing stage: cloud is made with extremely strong updrafts, raindrops begin to form, above freezing levels ice forms, the raindrops will reach a certain size where the updrafts can no longer hold them and they begin to fall.
· Mature Stage: Begins as soon as rain reaches the earth’s surface, updrafts and downdrafts throughout cloud, friction between the two drafts create lighting and turbulence, the cloud can even reach into the stratosphere, downdrafts will spill out creating a gust front.
· Dissipating stage: Entire cloud becomes a downdraft, which removes friction from updrafts, and things start to calm down.
List the hazards with thunderstorms
Turbulence, hail, icing, low visibility, low ceiling, lighting, precipitation static (interferes with radios), low level, wind shear, downbursts, better performance from wind shear then sudden worsening of performance
What should the distance be between you and thunderstorm?
How often are the surface analysis charts released?
4 times per day
How often are METARS issued
Every hour, on the hour, 24 hours a day
Is visibility given in NM or SM?
Is wind direction in degrees true or magenetic?
True, it’s true on paper, magnetic when spoken. This also applies to NM for spoken, SM on paper
How often are GFA’s released?
4 times per day
What is the difference with the last GFA produced?
it contains a 12 hour IFR outlook
What does 00000KT mean?
Light and variable