Meteorology Flashcards
Dry adiabatic lapse rate
3 degrees per 1000 ft
Saturated adiabatic lapse rate
1.5 degrees per 1000 ft
Dew point drop per 1000 ft
0.5 degrees
Unsaturated air temp. dew point closure rate
2.5 degrees per 1000 feet
How to calculate convective cloud base
Use temp/DP closure rate of 2.5 per 1000
How to calculate non-convective cloud base
use DALR of 3 per 1000
signs of warm front passage
Temp: increases
Pressure: decreases before and decreases slowly after passage
Wind: veers and increases
Type 1 and 4 deicing fluids
1: goes on hot with limited holdover
2; Goes on cold after type 1 meant to stop refreezing
DME frequency range
UHF
Order of precipitation when flying through a warm front
Warm to cold: Rain, freezing rain, ice pellets, snow
Alto/Cirro cloud heights
Alto- starts at 6500
Cirro- Starts at 20000
Wind speed required for mountain waves to occur
25kts
SCT is reported when there is ____ cloud coverage
3/8 to 4/8
Convective cloud spatial coverage codes and % covered
ISOLD = 25% or less
OCNL = 26% to 50%
FRQ = 50% or more
Signs of cold front passage
Temp - decreases
Pressure - Sharp decrease slightly before passage then increases as front passes
Wind: Veers and increases
GFA minimum winds published
Sustained speed of 20 kts
Gusts of 30 kts
FEW is reported when there is _____ cloud coverage
1/8 to 2/8
Mist is reported when vis. is _____
Equal to or greater than 5/8 SM
How to decode high level FD
Subtract 50 from direction, add 100 to speed
Conditions conducive to thunderstorms
-Steep lapse rate
-High moisture content
-lifting agent
TAF change group TEMPO
Temporary change in conditions lasting less than 1 hour
GFA forecast alt.
Below 24000 (400 mb)
BKN is reported when there is ____ cloud coverage
5/8 to less than 8/8
TAF change group PROB
There is a 30 or 40 percent chance that the condition will exist
Fog is reported when vis is _____
less than 5/8 SM
From how far away can you experience mountain waves?
150 NM from mountain peak
Air mass nomenclature
Moisture content:
-Continental = dry
-Maritime = moist
Temperature:
-Arctic = cold
-Polar = cool
-Tropical = warm
Upper front passage
No change in wind or temp. precipitation will still fall
CLR in AWOS report ?
What does AWOS mean?
CLR = no cloud below 10000
AWOS = automated weather observation system
AWOS vs human reporting
AWOS is more accurate except heavy rain or blowing snow cause erroneous readings
Standard meridians in Canada
AST-60W; EST-75W; CST- 90W; MST-105W; PST-120W
What happens to true altitude when temperature decreases
True altitude is lower in low temperature (altimeter reads higher)
Mountain waves effect on altimeter
Increased wind speed in waves cause decrease in pressure. altimeter reads higher (true altitude is lower)
Where do rotor clouds form?
Near the ridge of mountains
What is virga?
Falling rain that evaporates before it hits the ground. virga is the strong downdraft that remains
Distance to stay away from thunderstorm
20 NM
Thunderstorm stages
Developing - updrafts only
Mature - Updrafts and downdrafts/heavy rain/
Dissipating - Downdrafts only/rain
Carburetor icing highest risk temperature
-5 to +15
range control on airborne weather radar
Adjusts how far forward the pilot can see ahead of the aircraft but it does not change the amount of radar energy being transmitted.
Where does convergence happen
Center of a low
Freezing level line spacing on GFA
2500’ Intervals
How does frontal fog form `
Precipitation falls from warm air mass into cold ai mass
Upper level chart heights and hPa
850 hPa - 5000’
700 hPa - 10000’
500 hPa - 18000’
250 hPa - 34000’
Upper level chart contour spacing
60 meters (120 on 250 hPa chart)
When are winds reported as VRB
Less than 3 knots and variable direction
or stronger winds which direction is impossible to determine
Issue frequency of upper level and surface charts
0000Z and 1200Z (twice/day)
What does XX mean on upper level chart?
Cloud base is below forecast altitude
What is steam fog
Water vapor being introduced into cold air
Upper front on GFA symbol
normal front but unshaded
