Weather Flashcards
(81 cards)
1
Q
What are the levels in the atmosphere?
A
Troposphere, Tropopause, Stratosphere, Mesosphere, Thermosphere
2
Q
What is the Troposphere level?
A
Surface to 36,000 feet
3
Q
What is the Tropopause?
A
Lid of water vapor, between the Troposphere and Stratosphere
4
Q
What is Convection
A
Cold air sinks, hot air rises
5
Q
What are the 3 cells involved in atmospheric circulation?
A
Polar, Ferrel, Hadley
6
Q
How far does the polar cell extend before falling?
A
60 degrees latitude
7
Q
What are variations in altimeter settings between weather reporting points caused by?
A
Unequal heating of the earths surface.
8
Q
What do closer millibars mean?
A
Higher winds
9
Q
What are the 3 factors involved in Coriolis Force?
A
Distance traveled, Position on the earths surface (latitude), Speed of the object
10
Q
What rotation will high pressure result in?
A
Clockwise
11
Q
What rotation will low pressure result in?
A
Counterclockwise
12
Q
Explain frictional force.
A
Because of earths rotation and coriolis effect, wind is pushed to the RIGHT below 2,000 ft.
13
Q
What is the effect of friction on wind?
A
Wind will shift direction when near the earths surface.
14
Q
What is the result of convective circulation patterns associated with sea breezes?
A
Cool dense air moving inland from over the water.
15
Q
Convective circulation patterns associated with sea breezes are caused by what?
A
Temperature differences between land and sea.
16
Q
Is moist warm air stable or unstable?
A
Unstable
17
Q
What is sea breeze?
A
Warm land, cool water (daytime) blows from water.
18
Q
What is land breeze?
A
Cool land, warm water (night) blows from land.
19
Q
What is valley breeze?
A
Mountain slopes heated by the sun create upslope flow. (5-20 kts.)
20
Q
What is mountain breeze?
A
At night, high terrain cools off, becoming cooler than air below. Air flows downslope. ( 5-15 kts. Sometimes exceeding 25kts.)
21
Q
What is katabatic breeze?
A
Downslope wind, mostly referred to when stronger than mountain breeze
22
Q
Which is more stable? Dry cool air or Moist warm air?
A
Dry cool air
23
Q
Explain evaporation:
A
Liquid water converts to invisible water vapor.
24
Q
Explain Condensation:
A
Water vapor changes to liquid (this cloud development)
25
Explain Sublimination:
Ice to water vapor.
26
Explain Deposition:
Water vapor to ice.
27
Explain Humidity:
Moisture in the air
28
What is relative humidity?
Actual amount of moisture in air compared to the total amount of moisture that could be present at that temperature.
29
What is Dew Point?
Temperature at which the air must be cooled to become saturated.
30
What is Saturation?
Air contains 100% of moisture possible at a specific temperature.
31
Cloud forms calculation:
Temperature - Dewpoint / 4.4 X 1000
32
When does frost form?
When water vapor changes to ice on surfaces that are below freezing.
33
What is dew?
Water vapor from cool air that condenses on warmer objects.
34
What is condensation Nuclei?
Water droplets in air that form clouds.
35
What are low clouds?
Stratus, Stratocumulus, Nimbostratus, Fog
36
What is the height range for low clouds?
Surface to 6,500 feet
37
What are middle clouds?
Altostratus, Altocumulus
38
What is the height range for middle clouds?
6,500-20,000 feet
39
What are high clouds
Cirrus, Cirrostratus, Cirrocumulus
40
What is the height range of high clouds?
above 20,000 ft
41
Stratus Clouds
Horizontal layering with a uniform base. Flat, hazy, featureless clouds varying in color from dark gray to nearly white. May produce a light drizzle or a small amount of snow. These clouds are essentially above-ground fog (below 6,000 ft.)
42
Stratocumulus Clouds
generally appear as a low, lumpy layer of clouds that is sometimes accompanied by weak intensity precipitation. Stratocumulus vary in color from dark gray to light gray and may appear as rounded masses, rolls, etc., with breaks of clear sky in between (below 8,000 ft) hand size
43
Nimbostratus Clouds
This cloud typically forms from altostratus in the middle altitude range, but it tends to thicken into the low altitude range during precipitation. Although usually dark at its base, it often appears illuminated from within to a surface observer. Is a major precipition cloud and produces virga and rain columns (below 10,000 ft)
44
Altostratus Clouds
a cloud of a class characterized by a generally uniform gray sheet or layer, lighter in color than nimbostratus and darker than cirrostratus: of medium altitude. It can produce light precipitation, often in the form of virga. If the precipitation increases in persistence and intensity, the altostratus cloud may thicken into nimbostratus. (8000–20,000 ft
45
Altocumulus Clouds
A middle-level cloud either banded or rounded in formation. Sometimes, they look like balls of cotton stuck into the blue background of the sky, while other times they look like rows. Often, these clouds have shadows or dark areas and can sometimes signal bad weather is approaching. They are made of water whereas high-level clouds are made of ice. (6,500–20,000 ft) thumb size
46
Cirrus Clouds
The most common form of high-level clouds are thin and often wispy cirrus clouds also known as mares tails. They form when water vapor undergoes deposition. (above 20,000 ft)
47
Cirrostratus Clouds
sheet-like, high-level clouds composed of ice crystals. Though cirrostratus can cover the entire sky and be up to several thousand feet thick, they are relatively transparent, as the sun or the moon can easily be seen through them. (Above 20,000 ft)
48
Cirrocumulus Clouds
Have distinguishing characteristics displayed in a fine layer of small cloud patches. These small cloud patches are sometimes referred to as "cloudlets" in relation to the whole cloud formation.
Are formed from ice crystals and water droplets. Often, the water droplets in the cloud freeze into ice crystals and the cloud becomes a cirrostratus cloud. They usually only form as part of a short-lived transitionary phase within an area of cirrus clouds and can also form briefly as a result of the breaking up of part of a cumulonimbus anvil. (above 20,000 ft)
49
Cumulus Clouds
These are fair weather cumuliform clouds of limited convection that do not grow vertically. The vertical height from base to top is generally less than the width of the cloud base. They appear similar to stratocumulus but the elements are generally more detached and less wide at the base.
50
Cumulonimbus Clouds
known as a thunderstorm cloud. Form in very unstable air. A heavy and dense cloud of considerable vertical extent in the form of a mountain or huge tower, often associated with heavy precipitation, lightning and thunder. The mature Cumulonimbus cloud has a distinctive flat, anvil shaped top. (6,500–60,000 ft)
51
Stages of cumulonimbus clouds
development stage, mature stage, dissipation stage
52
Vertical cloud formation
Develop & turbulence from the lifting of unstable air.
(Cumulus & Cumulonimbus clouds)
53
Stable air
Stratiform clouds form causing restricted visibility, smooth air, steady rain or drizzle.
54
Unstable air
Cumuliform clouds, showers, turbulence, good visibility
55
Front
Boundary between air masses
56
Cold Front
Fast moving, catch up and merge with slower warm front creating an occluded front.
57
List the frontal discontinuities
Fast moving cold fronts, Slow Moving cold fronts, Warm fronts
58
Fast moving cold fronts create _______ \_\_\_\_\_\_\_\_
Unstable hazards
59
Slow moving cold fronts
Is relatively like a stationary front, bringing rain for quite a while as the front approaches, then when the front passes, it will bring cold weather for a longer period of time because the front will be around for a longer period of time
60
Warm fronts
is the transition zone where a warm air mass is replacing a cold air mass. Warm fronts generally move from southwest to northeast and the air behind a warm front is warmer and more moist than the air ahead of it.
61
Thunderstorms
unstable air, lifting force, high moisture
62
What are the different types of thunderstorms?
Single Cell, Super Cell, Multi Cell, Squall Line
63
This type of thunderstorm lasts about 1 hour
Single Cell
64
Super cell thunder storm will last how long?
up to 2 hours
65
What is a multi cell thunderstorm?
Compact cluster of thunder storms.
66
What is the most destructive type of thunderstorm?
Squall line
67
What is a squall line?
Thunderstorm that forms 50-300 miles ahead of a fast moving cold front
68
What 3 things should you do if you encounter turbulence?
Slow speed Maintain level flight Accept variations in altitude.
69
What are the different types of turbulence?
Low level, Mechanical, Convective, Wake
70
Low level turbulence occurs at what altitude?
Below 15,000 feet
71
Mechanical turbulence occur as a result of
obstacles
72
What type of turbulence is created by thermals?
Convective
73
Wake turbulence are caused by
wing vortices of heavy slow moving aircraft in a clean configuration
74
Clean air turbulence
is the turbulent movement of air masses in the absence of any visual cues such as clouds, and is caused when bodies of air moving at widely different speeds meet
75
Mountain wave turbulence
oscillations to the lee side (downwind) of a mountain caused by the disturbance in the horizontal air flow caused by the high ground.
76
Wind shear
Wind shear is a change in wind speed and/or direction over a short distance. It can occur either horizontally or vertically and is most often associated with strong temperature inversions or density gradients. Wind shear can occur at high or low altitude
77
Micro burst
A microburst is a small-scale downburst, thus a very localized column of sinking air caused by a small and intense downdraft (the air does not spin like it does in the case of a cyclone or tornado) within a thunderstorm. There are two types of microbursts: wetmicrobursts and dry microbursts.
78
Icing
Visible moisture is necessary for structural icing to form. Freezing rain usually produces the highest rate of ice accumulation
79
Virga
an observable streak or shaft of precipitation that falls from a cloud but evaporates or sublimes before reaching the ground. At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is often due to compressional heating, because the air pressure increases closer to the ground
80
Advection fog
occurs when moist air passes over a cool surface by advection (wind) and is cooled. It is common as a warm front passes over an area with significant snow-pack. It is most common at sea when moist air encounters cooler waters, including areas of cold water upwelling
81
Radiation Fog
is formed by the cooling of land after sunset by thermal radiation in calm conditions with clear sky. The cool ground produces condensation in the nearby air by heat conduction. In perfect calm the fog layer can be less than a meter deep but turbulence can promote a thicker layer. Radiation fogs occur at night, and usually do not last long after sunrise, but they can persist all day in the winter months especially in areas bounded by high ground. Radiation fog is most common in autumn and early winter
