Met Flashcards
ATIS
Released every time significant change in weather
Cloud in AGL
Only forecast where wind is magnetic
ARFOR
Area Forecast
Only forecast where cloud is AMSL
Released at 0600 and 1200 approx local time
ADFOR regions found AIP Vol 1 GEN 3.5
TAF
Terminal Area Forecast
Valid between time stated on TAF
Covers 8km radius from ARP
TEMPO
Valid for no longer than an hour at a time and cumulatively no longer than half the period stated
METAR
Released hourly, on the hour
Covers 8km radius from ARP
TREND
Aerodrome forecast
Valid for 2hrs at end of METAR or SPECI stating any significant changes
While valid it supersedes TAF
AUTO METAR
Released every 1/2 hour, 24 hrs a day, by auto weather station
SPECI
Released outside normal time period of METAR when there is significant change in weather that lasts > 10 mins
// = ?
Unable to detect weather
///
Cloud detected, unsure if CB or TCU
////
Vis not reported
/////////
Cloud not reported
NCD
No cloud detected
TAF and METAR use SKC
NDV
No directional variation can be reported
PLWR
Possibly lower
VC
In the vicinity 8-16km from ARP
Southern Hemisphere winds
Altitude increases =
Altitude decreases =
Alt. Increase = Wind backs and strengthens
Alt. Decrease = Wind beers and weakens
Veer = moves clockwise eg. From 270 to 290
Environmental lapse rate
1.98*C per 1000ft
Dry Adiabatic lapse rate
3*C per 1000ft
Saturated adiabatic lapse rate
1.5* per 1000ft
ELR > DALR and SALR =
Unstable atmosphere
ELR < DALR and SALR =
Stable atmosphere
DALR > ELR > SALR =
Conditionally stable atmosphere
Characteristics of stable air
Cloud - stratiform
Precipitation - Light to moderate continuous
Vis - Poor
Turbulence - Light to moderate
Characteristics of unstable air
Cloud - Cumuliform
Precipitation - Intermittent, showery, moderate to heavy
Vis - Good
Turbulence - Moderate to severe
HZ vis =
< 5000m
BR vis =
1000 - 5000m
FG vis =
< 1000m