Weather Flashcards

1
Q

Dew point

A

Air can’t hold any more moisture, saturated and begins to condensate
When water in air becomes visible as moisture, cloud, fog
Current temp more than 3 degrees from dew point to be safe

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2
Q

Atmosphere layers

A
Troposphere, up to 48k ft
Tropopause layer with Jetstream
Stratosphere 
Mesosphere
Thermosphere
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3
Q

Atmospheric circulation

A

Warm air rises at equator, moves up to poles, back down to equator

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4
Q

Atmospheric pressure

A

Decreases at one inch per 1000ft

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5
Q

Coriolis forces

A

Due to rotation of the earth
Northern hemisphere deflecting air to the right,eastward
Northeasterly trade winds from 30• to equator

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6
Q

Measuring atmospheric pressure

A

Aneroid vs mercurial barometer

Weather station pressure convertered to sea level, adding 1” Hg for every 1000ft

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7
Q

Currents and winds

A

Due to pressure differences, coriolis, friction, temperature differences
Upward, downward, horizontal
Cause weather changes

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8
Q

Cyclonic vs anti cyclonic circulation

A

Northern hemisphere high pressure deflection to the right clockwise pattern
Low pressure counterclockwise

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9
Q

High vs low pressure

A

High, descending dry air, good weather

Low, air flows into area to replace rising air, brings clouds, rain

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10
Q

Convective currents

A

Local circulation of air due to uneven heating of the ground, turbulence
Water, vegetation hearts slower

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11
Q

Low level wind shear

A

Dangerous

Due to passing frontal system, thunderstorms, temperature inversion, strong upper level wind

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12
Q

Microbursts

A
Servere type of low level wind shear 
Intense rain at the surface 
At cloud base ring of blowing dust 
1-2 miles diameter, depth of 1000ft
5-15min, downdrafts of up to 6000ft/min
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13
Q

Weather station symbols

A

Circle = station
Line points into direction where wind is coming from
Speed = barbs and pennants, 5, 10, 50

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14
Q

Isobars

A

Lines of equal pressure in mb
Close together = steep gradient, strong winds
Ridge = elongated area of high pressure
Trough = elongated area of low pressure

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15
Q

Adiabatic process

A

Heating and cooling off air when rising vs descending, temp lowers as air rises and expands
Moist air cools slower, rises higher, unstable

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16
Q

Inversion

A

Cool air below warmer air, at night, cool surface cools down few hundred feet of air, capped by top of layer

17
Q

How air can reach saturation point

A
  1. Warm air moves over cold surface
  2. Cold and warm air mix
  3. Air cools at night contact with cooler ground
  4. Air forced into high atmosphere
18
Q

Radiation vs advection fog

A

Ground cools rapidly, in valleys, air reaches dew point, vs

Wind pushes most warm air over cool surface, coastal fog

19
Q

Uplope vs steam vs ice fog

A

Wind pushes moist air up mountain range
Cold dry air moves over warm water causing water to evaporate
In arctic region, water vapor into ice

20
Q

Clouds

A

Air cools, reaches saturation point, deposition, sublimation, condensation, onto condensation nuclei (dust, salt, smoke)
Low - base up to 6500ft AGL
Middle - 6500-20k
High - above 20k

21
Q

Cloud classification

A
Cumulus
Stratus
Cirrus
Castellanus 
Lenticularus 
Nimbus
Fracto
Alto
22
Q

Ceiling

A

Lowest level of clouds reported as broken or overcast
Broken: 5/8 to 7/8 of sky covered
Overcast = 100% covered

23
Q

Cumulus clouds

A

Extensive vertical development
Base is low, extend high altitude
Instability, turbulence, thunderstorms
Lightning, hail, tornadoes, gusty, wind shear

24
Q

Precipitation

A

Drizzle, very small water droplets, fog
Virga, rain that evaporates before reaching the ground
Rain falling through temperature inversion may freeze, ice pellets

25
Q

Air masses

A

Based on source region
Take on surrounding characteristics
Polar, tropical, dry deserts
Moves over cold or warm land

26
Q

Front

A

Boundary layer between 2 air masses, chances in weather imminent
Warm, cold, stationary, occluded

27
Q

Warm front

A

Slow moving, moves over cooler air, pushes it out, high humidity, fog, rain, thunderstorms when warm air is lifted, barometric pressure falling
Stratiform clouds, cumulonimbus in summer

28
Q

Cold front

A

Move rapidly, close to ground, forcing warm air up, forming clouds
Cirriform, cumulus clouds, rain showers
Can produce tornadoes, poor visibility, gusty winds, temperature and dew point dropping

29
Q

Occluded front

A

Fast cold front catches up with slow warm front
Cold front occlusion, mixture of weather
Warm front occlusion, thunderstorms

30
Q

Thunderstorm conditions

A

Air with sufficient water vapor, unstable lapse rate, initial lifting action
Air mass storms (short) versus steady state storms (long)

31
Q

Squall line

A

Narrow band of thunderstorms, ahead of cold front, moist unstable air, wide and long, forms rapidly

32
Q

Tornado

A

Thunderstorm draw air into cloud with rotation, concentrated, 200kts winds, low pressure inside vortex, tornado of cloud touches ground, or waterspout, if water

33
Q

Thundering hazards

A
Turbulence 
Icing 
Hail 
Ceiling and visibility 
Lightning
Pressure
Engine water ingestion