Air Masses & Fronts
Air Masses & Fronts is a core knowledge area on the Aviation Weather FAA written exam. This hub collects our 6 in-depth, ACS-aligned air masses & fronts articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
Air Mass Source Regions and the Five-Type Classification
Air masses are classified by the temperature and moisture of their source regions into five types—cA, cP, cT, mP, and mT—each producing distinct weather as it moves and modifies over new terrain.
Air Mass Modification: Lake Effect and Surface Heating
Air masses change character as they migrate over new surfaces; lake-effect snow and surface heating are two of the most dramatic examples of that transformation, producing locally intense weather that catches pilots off guard.
Warm Fronts: Structure, Clouds, and Flight Hazards
A warm front forms when advancing warm air overrides retreating cold air, producing a broad zone of stratiform clouds, steady precipitation, and poor visibility that can extend hundreds of miles ahead of the surface boundary.
Cold Fronts: Fast-Moving Lift, Squalls, and Wind Shifts
Cold fronts force warm air upward steeply and rapidly, producing narrow bands of intense weather including thunderstorms, squall lines, and sharp wind shifts followed by quick clearing.
Stationary and Occluded Fronts: Warm vs. Cold Occlusions
Stationary fronts stall between equally matched air masses and produce prolonged weather, while occluded fronts form when a fast cold front overtakes a warm front—creating cold or warm occlusions with distinct, often severe weather hazards.
The Wave Cyclone Model and the Dryline
The wave cyclone model describes how mid-latitude low-pressure systems evolve from a stationary front through occlusion and dissipation, while the dryline is a moisture boundary across the High Plains infamous for spawning severe thunderstorms.
More Aviation Weather subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.