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77 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Troposphere Altitude
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surface to level to 36,000 ft AGL
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Jepp 6-3
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Tropopause
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Acts as a lid to confine most of the water vapor, and the associated weather, to the troposphere
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Jepp 6-3
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Levels and Layers
5 of them, from bottom up... |
Troposphere
Tropopause Stratosphere Mesosphere Thermosphere |
Jepp 6-3
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Stratosphere Altitude
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extends to a height of 160,000 ft AGL
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Jepp 6-3
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Composition of the Atmosphere
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78% Nitrogen
21% Oxygen 1% Other gases |
Jepp 6-4
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Atmospheric Circulation
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the movement of air relative to the E's surface
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Jepp 6-5
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Convection
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Circulation process - cool, heavy air tends to sink and replace warmer, rising air
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Jepp 6-6
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Isobars
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Lines of equal pressure, measured in millibars
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Jepp 6-7
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Pressure gradient
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change in pressure over distance
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Jepp 6-7
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Ridge
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An elongated area of high pressure,
denoted by a zig-zag line ~~~ |
Jepp 6-7
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Trough
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An elongated area of low
denoted by a dashed line - - - - |
Jepp 6-7
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Coriolis Effect
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the apparent deflection of an object moving across the face of the Earth; due to the Earth's rotation
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Jepp 6-8
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The magnitude of the Coriolis Effect depends on
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Speed (the greater the speed, the greater the deviation)
Latitude (zero at the equator, increases toward the poles) |
Jepp 6-8
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Frictional Force
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within about 2000 feet of the ground friction caused by the Earth's surface slows the moving air, reducing the Coriolis Effect
causes the wind to blow at an angle across the isobars |
Jepp 6-9
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Low pressure exists...
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Over the equator and at 60* latitude
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Jepp 6-10
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High pressure exists...
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near 30* latitude and the poles
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Jepp 6--10
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The Hadley Cell, From 0* to 30* Latitude winds are called
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Northeast Trade Winds
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Jepp 6-10
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The Ferrel Cell, From 30-60* Latitude winds are called
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Prevailing Westerlies
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Jepp 6-10
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The Polar Cell, From 60* to the Pole winds are called
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Polar Easterlies
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Jepp 6-10
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Advection vs Convection
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Convection = vertical movement (hot air rises, cold air falls)
Advection = horizontal movement (from High to Lo pressure) |
Notes, Lesson 9
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Local Wind Patterns
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Sea Breeze
Land Breeze Valley Breeze Mountain Breeze Katabatic Winds -cold downslope & warm downslope winds |
Jepp 6-11
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Standard Lapse Rates
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For every 1000 feet in altitude...
-Temperature decreases 2*C -Pressure decreases 1 in Hg |
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International Standard Atmosphere
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At Sea Level....
Barometric pressure of 29.92 Temperature of 15*C |
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Pressure Systems
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caused by uneven heating of the Earth
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Notes, Lesson 8
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29.92
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Standard Pressure at sea level in inches of Mercury
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Notes, Lesson 8
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1013.25
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Standard Pressure at sea level in millibars
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Notes, Lesson 8
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High Pressure
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-an area surrounded by lower pressure
-airflow pattern is clockwise, down and out |
Notes, Lesson 8
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Low Pressure
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-an area surrounded by higher pressure
-airflow pattern is counterclockwise, up and in |
Notes, Lesson 8
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Dew Point
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-temperature at which air must be cooled to condense into water
-visible moisture when at that temperature |
Notes, Lesson 8
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If Dew Point = Temperature,
What is the relative humidity? |
100%
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Notes, Lesson 8
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VCTIP characteristics of Stable Air
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Visibility ---------- Poor...
Clouds are ------- Stratiform... Turbulence, ------ light or none... Icing is ------------- Rime Ice... Precipitation is -- Steady |
Notes, Lesson 8
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VCTIP characteristics of Unstable Air
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Visibility is ---------- Good...
Clouds are ---------- Cumuliform... Turbulence is ------ moderate to extreme... Icing is --------------- Clear... Precipitation is ---- Showery... |
Notes, Lesson 8
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Sea Breeze vs Land Breeze
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Sea breeze blows from cool water to warmer land during the day
Land breeze blows from the cooler land to the warmer water at night |
6-14
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Cold downslope wind
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flows downhill from snow-covered plateaus or steep mountain slopes
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6-14
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Warm downslope wind
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sometimes dramatically raise the temperature at the base of the mountain
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6-14
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Stability
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The atmosphere's resistance to vertical motion
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6-16
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Contrail
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-produced by jets flying between 25,000 and 40,000 feet
-in moist air |
ch 6 section B
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Upslope Fog
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-forms when moist, stable air is forced up a sloping landmass
-moderate to strong winds -under cloudy skies |
ch 6 section B
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Advection Fog
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-a low layer of warm, moist air moves over a cooler surface
-winds up to 15 kts |
ch 6 section B
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Radiation Fog
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-forms in moist air
-over low, flat areas -on clear, calm nights |
ch 6 section B
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Clouds with Vertical Development
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-from low to middle (6,500 to 20,000)
-extending above 20,000 -----cumulus -----towering cumulus -----cumulonimbus |
ch 6 section B
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High Clouds
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-above 20,000 ft AGL
-----cirrus -----cirrostratus -----cirrocumulus |
ch 6 section B
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Middle Clouds
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-from 6,500 to 20,000 ft AGL
-----altostratus -----altocumulus |
ch 6 section B
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Low Clouds
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-up 6,500 ft AGL
-----stratus -----stratocumulus -----nimbostratus |
ch 6 section B
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Dewpoint
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Temperature to which the air must be cooled to become saturated
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ch 6 section B
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Relative Humidity
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The actual amount of moisture in the air compared to the total amount that could be present at that temperature
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ch 6 section B
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Sublimation
vs Deposition |
SUBLIMATION = changing of ice directly to water vapor
DEPOSITION = transformation of water vapor to ice |
ch 6 section B
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Latent Heat of Evaporation
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As water vapor forms, heat is absorbed from the nearest available source (e.g. sweating cools you down...)
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ch 6 section B
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Latent Heat of Condensation
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the heat absorbed by water vapor during evaporation is released; an important factor in cloud development
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ch 6 section B
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Temperature Inversions
(features) |
A smooth, stable layer of air
....and a temperature increase with altitude ....visibility is often poor |
ch 6 section B
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Air that is both cool and dry...
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resists vertical movement and is very stable
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ch 6 section B
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The greatest instability occurs when the air is...
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both moist & warm
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ch 6 section B
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Moist Adiabatic Lapse Rate
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1.1*C to 2.8*C per 1000 feet
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ch 6 section B
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Dry Adiabatic Lapse Rate
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3*C per 1000 feet
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ch 6 section B
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When a parcel of air
RISES Pressure ________ Volume _________ Temperature ______ |
-Pressure decreases
-Volume increases -Temperature decreases |
ch 6 section B
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When a parcel of air
DESCENDS Pressure _______ Volume_________ Temperature ________ |
When a parcel of air descends
-Pressure Increases -Volume Decreases -Temperature Increases |
ch 6 section B
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Warm Front
Prior to Passage (7 Things) |
Clouds - Cirriform, Stratiform, Fog, Possible Cumulonimbus
Precip- light to moderate rain, drizzle, sleet or snow Visibility- Poor Wind- SSE Temp- Cool to cold Dewpoint- Rising steadily Pressure- Falling |
6-33
Fig 6-35 |
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Cold Front
Prior to Passage (7 Things) |
Clouds- cirriform, towering cumulus &/or cumulonimbus
Precip- Showers Visibility- Fair in haze Wind- SSW Temp- Warm Dewpoint- High Pressure- Falling |
6-32
Fig 6-34 |
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Warm Front
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Warm air overtakes and replaces cooler air
-much slower speeds than cold fronts |
6-33
Fig 6-35 |
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Cold Front
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Cold air displaces warmer air
Can be Fast or Slow Moving (see Fig 6-34) |
6-32
Fig 6-34 |
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Front
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Boundary between airmasses
(review types 6-30) |
6-30
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Cooling from Below
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An airmass flows over a cooler surface,
its lower layers are cooled & vertical movement is inhibited ---STABILITY is increased |
6-30
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Warming from Below
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An airmass moves over a warmer surface,
its lower layers are heated, & vertical movement develops ---INSTABILITY |
6-29
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Source Regions
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The location an airmass acquires the properties of temperature and moisture that determine stability (polar regions, tropical oceans, large deserts)
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6-28
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Airmass Classifications
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mP - Cool and Moist
mT - Warm and Moist cP - Cool and Dry cT - Hot and Dry |
6-28
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Airmass
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A large body of air with fairly uniform temperature and moisture content
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6-28
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Precipitation Induced Fog
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Warm rain falls thru a layer of cooler air near the surface, evaporation from the precipitation may saturate the cool air
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Low-Level Turbulence (LLT)
below 15,000 ft MSL -4 types- |
-Mechanical
-Convective -Frontal & -Wake Turbulence |
6-44
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Occluded Fronts
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When fast moving cold front catches up with slow moving warm front
(2 kinds 6-33) |
6-33
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Wake Turbulence
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-rotating whirlpools of air caused by an a/c generating lift (wing-tip vortices)
-Intensity depends on a/c weight, speed and configuration |
6-47
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Frontal Turbulence
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-Updrafts can reach 1000 f.p.m.
-Just ahead of fast moving cold fronts |
6-47
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Microburst
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-A Precip-Induced downdraft
-winds in excess of 100 kts -downdrafts as strong as 6000 f.p.m. |
6-51
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Wind Shear
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A sudden, drastic shift in wind speed or direction that may occur at any altitude in a vertical or horizontal plane
Often associated with convective precipitation |
6-50
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Mountain Wave Turbulence
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-Anticipated if wind is >25 kts and is perpendicular to mountain ridges
-fly 3000-5000 ft above the peaks for avoidance -approach ridge at a 45* angle -cap, roll and lenticular clouds can signal mtn wave activity |
6-49
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Clear Air Turbulence (CAT)
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-often present with no visual warning
-A layer of air slides over the top of another, relatively slower moving layer - may cause waves ~ ~ ~ ~ |
6-48
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Convective Turbulence
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Occurs in fair weather
Caused by currents or thermals |
6-45
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Mechanical Turbulence
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Produced downwind of obstructions
Can reach altitudes in excess of 3000'AGL |
6-44
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