Weather Charts and Meteorological Information Services
Concepts to master
Know the main chart types: surface analysis, upper-air charts (850, 700, 500, 250 hPa), significant weather (SIGWX) charts, and prognostic charts. Understand how to read isobars, contour heights, troughs, ridges, and jet stream positions. Know the roles of meteorological services: Environment and Climate Change Canada (ECCC) aviation forecasts, NAV CANADA flight information services, and the availability of METAR, TAF, GFA, SIGMET, and AIRMET through aviation weather websites and flight planning services.
Understand chart symbols: fronts, pressure centres, and the meaning of the 500 hPa chart for steering and stability. Know that SIGWX charts depict significant en-route weather such as Cb, turbulence, icing, and jet streams.
Traps
Questions often confuse the 500 hPa chart with the surface chart, or misinterpret contour heights as pressure. Another trap is assuming all charts are valid at the same time or that a SIGWX chart replaces a TAF.
Rule of thumb
Use surface charts for fronts and pressure, upper-air charts for steering and stability, and SIGWX charts for en-route hazards. Always check the valid time.