Forecasts and Advisories: TAF, GFA, SIGMET, AIRMET, and Warning Products
What to know
Understand TAF structure: issue time, validity period, wind, visibility, weather, sky, and change groups (FM, TEMPO, BECMG, PROB). Know the difference between a temporary fluctuation and a becoming condition. Understand the Graphical Area Forecast (GFA) domains and panels (cloud/weather and icing/turbulence), and how to read the associated symbols and labels. Know SIGMET criteria (severe turbulence, severe icing, volcanic ash, tropical cyclone, and other significant hazards) versus AIRMET (moderate hazards affecting low-level operations). Recognise the role of warning products such as public and aviation warnings, and the meaning of an AIRMET for IFR conditions.
Traps
Questions often confuse TEMPO with BECMG, or misapply SIGMET criteria to moderate hazards. Another trap is assuming a PROB30 group is a forecast certainty. Watch for the validity period boundaries and the difference between GFA panels.
Rule of thumb
If the hazard is severe or involves volcanic ash, think SIGMET; if moderate and affecting lower-level flights, think AIRMET. TEMPO means temporary fluctuations; BECMG means a gradual, permanent change.