Weather Charts, Briefings and Flight Planning Application
Charts
Candidates must interpret surface synoptic charts (isobars, fronts, highs, lows, troughs), significant weather charts (SIGWX), upper-wind and temperature charts, and prognostic charts. On a surface chart, closely spaced isobars mean strong wind; a tight gradient near a front signals a squall line. On upper charts, isotachs show jet-stream cores and CAT risk. The 500 hPa chart indicates troughs and ridges steering surface systems.
Briefings
A complete briefing covers route, altitude, time, aircraft type and pilot experience. It includes synopsis, en-route weather, terminal forecasts, winds aloft, freezing level, turbulence, icing, SIGMETs and NOTAMs. Self-briefing products include METAR/TAF, GAMET, SIGWX and wind/temperature charts. Verify the validity time and the trend before departure.
Flight planning application
Use winds aloft for fuel and time; account for temperature error in altimetry; plan alternates based on forecast visibility and cloud base; consider freezing level for icing; identify escape routes around convective areas. Cross-check forecast against actual METAR/SPECI at departure and destination.
Traps
Questions confuse the meaning of isobar spacing or misread upper-wind direction (from which the wind blows). Others forget that prognostic charts have validity periods and that SIGMETs supersede routine forecasts.
Worked example
A 500 hPa chart shows a deep trough west of the route with a 100 kt isotach. Expect strengthening southwesterly winds, CAT risk near the jet, and a cold front approaching from the west - plan fuel and alternate accordingly.
Rule of thumb
Tight isobars = strong wind; a deep upper trough = unsettled weather downstream; always check the freezing level and SIGMETs before departure.