Weather Flashcards
What is a METAR
Meteorological Areodrome Report
Current/observed weather updated every 50 min. Past the hour
What is Dewpoint
Temperature at which air becomes fully saturated
When should you expect to see fog?
When temperatures and dewpoint are within 2° Celsius of each other
What is a TAF
Terminal Aerodrome Forecast
Valid for 24 hours, updated every 6 hours
Only acceptable to use within 5sm of airport
What should you use if there is no TAF ?
Use Aviationweather.gov
What weather information can you obtain from graphical forecast
Cloud coverage
Ceilings
Winds
Storms
Etc.
Flight Categories
LIFR = LOW INSTRUMENT FLIGHT RULES (magenta)
Ceiling below 500’ AGL, visibility LESS than 1 mile
IFR= INSTRUMENT FLIGHT RULES ( red)
Ceilings 500’ to below 1000’ AGL, visibility 1 - less than 3 miles
MVFR= MARGINAL VISUAL FLIGHT RULES (blue)
Ceilings 1,000’ to 3,000’ AGL, visibility 3 - 5 miles
VFR= VISUAL FLIGHT RULES (green)
Ceilings greater than 3,000’ AGL, visibility greater than 5 miles
When is an Airport Beacon Lit?
IFR Weather conditions during daytime or at night
What are winds aloft
Forecasted wind speeds and direction at various altitudes
At what altitude are winds aloft assumed negative
24,000 MSL
What are characteristics of a high pressure system
Clockwise, outwards, and downwards
Poor visibility
Brings higher pressure / density
Characteristics of a low pressure system
Counterclockwise, inwards, and upwards
Good visibility
Includes precipitation because of higher humidity
What is a warm front
Slow moving, so gradual change
Stratiform clouds
Poor visibility because air is stable and calm
Steady precipitation
What are the characteristics of a cold front
Travels more rapidly than warm fronts,
Dense masses of air that remain close to the ground and displace warm air upward over itself.
The ascending air rapidly cools down forming clouds
Typically a formation of Cumulus clouds
Possible rapid development of thunderstorms
Showery precipitation
Eventually good visibility prevails once the cold front dominates the area
Barometric pressure will rise, because cold air is more dense
What is a stationary front
When cold and warm front meet and stop movements
Lingers for a long time
What is a occluded front
When one front catches up to another front moving in the same direction
Usually a cold front catches up to a slow moving warm front
Bravo cloud clearance
3sm
Clear of clouds
Charlie / Delta cloud clearance
[3-152]
3 sm of visibility
1000’ above
500’ below
2000’ horizontally
Echo cloud clearance
Below 10,000’ MSL [3~152]
3sm vis., 1000’ above, 500’ below, 2000’ horizontally
Above 10,000 MSL [5~111]
5sm vis., 1000’ above, 1000’ below, 1 mile horizontally
Golf airspace cloud clearance
Below 1200’ AGL
Day = 1sm visibility, clear of clouds
Night = 3sm visibility, 1000’ above, 500’ below, 2000’ horizontally
Above 1200’ AGL
Day = 1sm visibility , 1000’ above, 500’ below, 2000’ horizontally
Night = 3sm, 1000’ above, 500’ below, 2000’ horizontal
What are iso bars
Pressure measured in millibars
When close together expect higher winds
What is a Airmet
Airmen’s meteorological Information
Valid for 6 hours
Contains moderate weather conditions
What are the 3 Airmet weather designations
○ Tango - Turbulence, >30kt winds, Low level wind shear
○ Sierra - IFR conditions, mountain obscurations
○ Zulu - Freezing
What are the 3 types of ice
Structural Ice
Instrument icing
Induction icing
What is a SIGMET
Significant Meteorological Information
○ Valid 4 hours
○ Stronger weather phenomena that will affect safety of all aircraft
○ Severe or greater turbulence
○ Dust or sandstorms, Volcanic ash
○ Severe or greater icing
What is a Convective SIGMET
Sigmet related to convective activity
○ Valid 2 hours
○ Thunderstorms
○ Winds >50 kt winds
○ Hail 3⁄4” diameter or greater
○ Tornadoes
What 3 ingredients make a thunderstorm
Moisture
Uplifting action
Unstable air
What is unstable air
Normal temp decreases 2 celsius per 1000’, unstable is 3° per 1000’
What are the 3 stages of a thunderstorm
■ Cumulus
● Large updrafts
● Clouds are building in form and height
■ Mature
● Both up/downdrafts
● Extreme precipitation
● Lightning
■ Dissipating
● Mostly downdrafts
● Microburst is localized and can reach downdrafts of up to 6000’ a minute
● Storm weakens in intensity
What are the 3 types of structural icing
Rime
Clear
Mixed
