Meteorological Observations, Reports and Codes
This domain tests fast, accurate decoding and encoding of METAR, SPECI, TAF, SIGMET and PIREP.
METAR and SPECI
Format: report type, ICAO station, time DDHHMMZ in UTC, wind dddffKT with G for gusts and VRB for variable, visibility in metres (9999 means 10 km or more), RVR, present weather (intensity, descriptor, precipitation, obscuration), cloud amount and height as FEW/SCT/BKN/OVC in hundreds of feet AGL, temperature and dew point, QNH as Qnnnn hPa, and a trend group (NOSIG, BECMG, TEMPO). CAVOK means visibility 10 km or more, no cloud below 1,500 m and no significant weather. SPECI is issued for significant deterioration or improvement.
TAF
Validity period, wind, visibility, weather and cloud, plus change groups: FM for rapid change, BECMG for gradual change, TEMPO for temporary fluctuations, and PROB30 or PROB40 for probability.
SIGMET and PIREP
SIGMET warns of en-route hazards: thunderstorms, turbulence, icing, volcanic ash, tropical cyclones, duststorms and low-level wind shear. PIREP is a pilot report of actual conditions aloft.
Worked example
METAR OPRN 121200Z 24010KT 4000 HZ SCT040 32/18 Q1005 decodes as: Islamabad, 12th at 1200 UTC, wind 240° at 10 kt, visibility 4,000 m in haze, scattered cloud at 4,000 ft, temperature 32°C and dew point 18°C, QNH 1005 hPa.
Traps
Cloud heights are hundreds of feet AGL, not metres; METAR and TAF winds are true, not magnetic; all times are UTC; Q is QNH, not QFE; 9999 means 10 km or more.