Aeronautical meteorological reports, forecasts and warnings (METAR, SPECI, TAF, trend, SIGMET, AIRMET, GAMET, ICAO abbreviations)
This domain tests decoding and using METAR, SPECI, TAF, trend, SIGMET, AIRMET, GAMET and ICAO abbreviations.
METAR and SPECI
A METAR is a routine aerodrome observation; SPECI is a special report when conditions change significantly. Format: report type, station, time in UTC, wind, visibility, RVR, present weather, cloud, temperature and dew point, QNH, trend. Visibility 9999 means 10 km or more; four digits give metres. Cloud amounts are FEW, SCT, BKN and OVC, with height in hundreds of feet. Trend groups are NOSIG, BECMG and TEMPO.
Forecasts and warnings
TAF is an aerodrome forecast with a valid period; FM indicates a rapid change, BECMG a gradual change and TEMPO a temporary fluctuation. SIGMET warns of hazardous en-route weather such as thunderstorms, icing, turbulence, volcanic ash and tropical cyclones. AIRMET covers lower-level hazards. GAMET is a plain-language area forecast for low-level flights. ICAO abbreviations include KT, HPA, CAVOK, SH, TS, FZ, BR, HZ and DU.
Worked example
METAR DNMM 121200Z 21012G24KT 180V240 9999 SCT010 BKN020 29/24 Q1010 NOSIG. Decode: Lagos, 12th at 12:00 UTC; wind 210° at 12 kt gusting 24 kt, varying 180–240°; visibility 10 km or more; scattered cloud at 1,000 ft, broken at 2,000 ft; temperature 29°C, dew point 24°C; QNH 1010 hPa; no significant change expected. The 5°C spread makes convective cloud plausible but none is reported.
Traps
9999 is not unlimited visibility in metres. BKN is not overcast. QNH is not QFE. TAF times are UTC. TEMPO does not mean the change persists for the whole period.