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76 Cards in this Set
- Front
- Back
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Wind direction is always expressed in terms of the direction _____ which it is blowing.
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FROM
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On the station model depiction wx conditions, what does the circle mean? The square?
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Circle = automated stations; square = manned stations
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On the wind barb, how many knots is the wind blowing if you see one pennant?
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50 knots/pennant; ALSO know a long barb is 10 knots and a short barb is 5 knots
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What do large scale wind patterns transfer?
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Water vapor to include FOG, CLOUDS, and PRECIP
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What are pressure gradients?
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Rate of change in pressure in horizontal distance
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Pressure Gradient Force is the initiating force for all _____.
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winds
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Pressure gradient force flows ______ to isobars.
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perpendicular
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Isobars close together are indicative of a ____pressure gradient
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steep
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A steep pressure gradients are indicative of a ____ pressure gradient force.
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strong
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A strong Pressure gradient has ____wind speed
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higher
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Wide isobar spacing is indicative of a ____ pressure gradient
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shallow
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Shallow pressure gradients are indicative of a _____ pressure gradient force
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weak
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A weak pressure gradient force is produces ____ wind speed
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slower
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Air _____ in high pressure areas and flows _____ of the high
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descends; out
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What type of pressure area involves a horizontal wind diverging force?
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High pressure area
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Air ____ in low pressure areas and flows ____ the low
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ascends; into
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What does the Coriolis force do?
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The Coriolis force is created by the earths rotation and directs air to the right in BOTH highs and lows.
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What is the result of the PGF and Coriolis force?
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Gradient winds
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Which way do gradient winds flow?
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Perpendicular to the PGF and Paralle to the isobars
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Where are gradient winds found?
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above 2000 AGL
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What acauses wind to blow across isobars at a 45 degree angle?
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Surface friction
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What is the jet stream?
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narrow band of strong winds of 50kts or more found below the tropopause
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What is the average height and speed of the jet?
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30,000 feet MSL; 100-150 knots but could be up to 250 knots
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What are the aircrew considerations for flying in the jet?
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as headwind increases fuel consumption and windshear may also cause turbulence
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Air movement from sea to land is called
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a sea breeze
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Explain the sea breeze process
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Pressure over the land is lower than that of the water. Cool ocean air moves to low pressure and replaces warm land air. 15-20 knots
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Explain land breeze
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Pressure over the sea AT NIGHT is lower than that of the land. Warm air over the water rises, descends over the land and cooler air flows offshore.
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What is stronger…sea breezes or land breezes?
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sea breezes
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What type of winds flow out of a valley during the day?
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Valley winds
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What type of breeze flows downslope at night?
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Mountain breeze
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In a mountain breeze, air is ____ by outgoing land ____, becoming more
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cooled; radiation; dense
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What are the three types of atmospheric moisture?
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soild, liquid, and gas
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What is the hydrologic cycle?
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precip, evaporation, and condensation
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When air contains the maximum amount of vapor in can hold for a specific temp that air is considered to be ____.
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saturated
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What is the dew point temp?
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temp at which saturation occures
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If you have a high temp, you'll have ____ moisture in the air.
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more
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Can dew point temp ever be higher than acutal air temp?
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No
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The degree difference between air temp and dew point temp is called
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dew point depression or spread
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When you have a 4 degree dew point spread, the air is holding close to the ____ water vapor possible
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max. Also at 4 degree difference, RH will be approx 90%
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Relative Humidity (RH) is ___.
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the percentage of water vapor in the air compared to the max amount the air can hold at that temp.
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What are the three CHARACTERISTICS of precip?
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Showers, continuous, intermittent
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Precip that startsm stops, changes intensity rapidly and is associated with cumuliform clouds is ___.
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Showers
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Continuous (STEADY) precip ______.
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changes intensity gradually, if at all and is associated with stratiform clouds.
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Precip that stops and restarts at least once during the hour and is showery OR steady is called
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Intermittent precip and can have either cumuliform or stratiform clouds.
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What are the three TYPES of precipitation forms?
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Drizzle, rain, and frozen
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Drizzle is _____.
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Small droplets of water that appear to float in the atmosphere
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Water droplets larger than drizzle that fall to the ground is called ____.
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Rain
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Some types of frozen precip are ___.
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hail, ice pellets, snow, and snow grains
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The most important element in the formation of clouds is
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water vapor
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Condensed water vapor consisting of water droplet or ice crystal is called
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a cloud
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Condensation nuclei are ___.
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microscopic solid particles suspended in air that provide condensation surfaces
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Low clouds are found
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SFC-6,500 AGL
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Two different types of coulds you'd find in the low clouds category are
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Stratus (steady) and cumulus (showery)
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Why would ice accumulate faster in low clouds?
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B/c low clouds are more dense than middle/high clouds
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Middle coulds are found where?
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6500-20000 AGL
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What type of wx conditions would you find in middle clouds?
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light precip, common icing. Ice crystals and water droplets mix in these clouds
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In middle clouds, you'd find these specific types of clouds.
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ALTOstratus (light showery or steady precip) and ALTOcumulus
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High coulds range from what alt to what alt?
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20000-40000 AGL
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In high coulds will you find precip?
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No…they are composed of ice crystals and these clouds are not an icing hazard.
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In high clouds, you'd find these specific types of clouds?
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CIRROcumulus, CIRROstratus and CIRRUS
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The two types of special clouds are ____ and ____.
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towering cumulus and cumulonimbus
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Nimbostratus clouds produce ____.
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VIOLENT, HEAVEY, STEADY precip
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The atmospheric tendency to return toward initial condition when disturbed is called ___.
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a stable atmosphere
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Neutrally stable air wil _____.
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remain in its new state.
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Unstable air will
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move awayy from its initial condition when disturbed
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What type of clouds are associated with stable air?
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Stratiform
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After being lifted, stable air is _____ than the surrounding air.
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Colder
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When the lifting is removed, stable air will ____.
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settle
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Neurtally stable air has the ___ temp as the surround ari after being lifted.
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same
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The air stablity that causes air to remain at the same place until acted upon by something else is called ___ ____ ___.
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neutrally stable air and has about the same results as stable air
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The tyoe of clouds associated with unstable are are ___.
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Cumuliform clouds
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After being lifted, unstable air is ____ than the surrounding air.
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warmer
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The four methods of lifting are:
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convergence, frontal, orographic, and thermal
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In stable flight conditions you will find:
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(S-S-S-S) Stratus clouds, smooth air, steady winds, and steady precip. Also rime icing and poor vis.
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Unstable flight conditions are
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Cumulus clouds, rough air, good vis, gusty winds, showery precip, clear icing, and T-storms.
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The __ is used to determine air mass boundary
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dew point
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