Meteorology
Atmosphere and stability
Know the standard atmosphere: 15 °C at sea level, lapse rate of about 2 °C per 1,000 ft in the troposphere, and the tropopause. Understand stability: a stable atmosphere resists vertical motion and produces stratiform cloud and steady precipitation; an unstable atmosphere produces cumuliform cloud, showers, and turbulence.
Pressure and wind
Know the relationship between pressure gradient and wind speed, and the effect of Coriolis and friction. Understand the difference between true and magnetic wind, and how wind shear and microbursts affect approach and departure. Know the meaning of QNH, QFE, and standard pressure (1013.25 hPa), and the transition altitude and level.
Cloud and icing
Know the cloud types and the icing risk: clear ice in large supercooled droplets, rime ice in smaller droplets. Know that freezing rain indicates a warm layer aloft.
Traps
- Confusing QNH (altitude above mean sea level) with QFE (height above the aerodrome).
- Assuming all cumulus cloud is dangerous; only certain types produce severe weather.
- Forgetting that the tropopause height varies with latitude and season.
- Mixing up the transition altitude (fixed by the state) and the transition level (varies with QNH).
Worked example
If the surface temperature is 20 °C and the dew point is 12 °C, the spread is 8 °C; the convective cloud base is roughly 4,000 ft (spread × 400 ft per °C). Apply this rule of thumb to estimate cloud base.