FAA Airline Transport Pilot (ATM)Meteorology and Weather ServicesMedium
A dispatcher is briefing a flight into an area where a cold front is overtaking a slower-moving warm front. What frontal system is forming, and what weather characteristic is typical?
- AA squall line forming well ahead of the warm front
- BA dry line with blowing dust and low humidity
- CAn occluded front, combining characteristics of both cold and warm fronts
- DA stationary front with persistent light precipitation
Show answer & explanationAnswer & explanation
Correct answer: C. An occluded front, combining characteristics of both cold and warm fronts
An occluded front forms when a faster-moving cold front catches up to and overtakes a slower warm front, lifting the warm air aloft. Weather along an occlusion combines characteristics of both cold and warm fronts, often producing widespread precipitation and complex cloud structures.
Why the other options are wrong
- A. A squall line is a line of thunderstorms, not the result of frontal overtaking.
- B. A dry line separates moist and dry air masses and is unrelated to this scenario.
- D. A stationary front has no relative movement between air masses, not the case here.
Occluded Front
A frontal boundary formed when a fast-moving cold front catches up to a slower warm front, lifting the warm air mass off the surface.
- Combines cold front and warm front weather characteristics
- Two types: cold-type and warm-type occlusion
- Often associated with the mature/dissipating stage of a mid-latitude cyclone
Memory trick: Cold front chases down warm front — they collide into an occlusion