Meteorology for Instrument Flight
Instrument pilots must translate weather products into go/no-go and en-route decisions. Know the structure of a front: warm fronts produce widespread stratiform clouds and steady precipitation well ahead, while cold fronts bring narrow bands of convective activity and rapid visibility loss. Understand stability and lapse rates, and how an inversion traps moisture and haze beneath it. Study icing: clear ice forms in large supercooled drops at temperatures near 0 to −10 °C, rime ice in smaller drops at colder temperatures, and freezing rain signals a warm layer aloft. Know the hazards of low-level wind shear, microbursts, and mountain wave turbulence.
Questions often test interpretation of METAR and TAF groups: prevailing versus temporary conditions, the meaning of a broken versus overcast ceiling for alternate minima, and how visibility is reported in statute miles. Another trap is confusing an AIRMET with a SIGMET: SIGMETs cover severe or hazardous conditions such as severe turbulence, severe icing, and volcanic ash, while AIRMETs cover moderate hazards affecting light aircraft. Ceiling and visibility minima for an alternate depend on the approach available, not on the destination forecast alone.
Rule of thumb: a ceiling is the lowest broken or overcast layer; scattered layers do not count. Worked example: a TAF shows "BKN008 OVC015 2SM BR" for the arrival window. The ceiling is 800 ft, which is below a 1,000-ft ceiling requirement, so the airport cannot serve as a destination under those minima.