FAA Aircraft Dispatcher (ADX)MeteorologyHard
A dispatcher analyzing a surface analysis chart notes an occluded front where the air behind the front, at the surface, is warmer than the air ahead of the front. How should this occlusion be classified?
- AStationary occlusion
- BWarm-type occlusion
- CDryline occlusion
- DCold-type occlusion
Show answer & explanationAnswer & explanation
Correct answer: B. Warm-type occlusion
A warm-type occlusion occurs when the air mass behind the occluded front (following the cold front) is relatively warmer than the air mass ahead of the front (ahead of the warm front), typically because the overtaking cold air is not as cold as the air it is displacing. This type is common along the Pacific coast of North America.
Why the other options are wrong
- A. Stationary front is a distinct front type with little to no movement, not a classification of occlusion type.
- C. A dryline is a moisture boundary common in the central U.S., unrelated to occlusion classification.
- D. A cold-type occlusion occurs when the air behind the front is colder than the air ahead, the opposite of this scenario.
Occluded Front Types
An occluded front forms when a fast-moving cold front overtakes a slower warm front. It is classified as cold-type if the overtaking air is colder than the air ahead, or warm-type if the overtaking air is warmer than the air ahead.
- Cold-type occlusion: overtaking cold air is colder than the air it displaces, common in central/eastern regions
- Warm-type occlusion: overtaking air is milder than the air ahead, common along the Pacific Coast
- Occluded fronts often bring extended periods of precipitation and cloudiness
Memory trick: 'Warm-type occlusion: the sneaky new air is Warmer, so it rides up and over — like on the West coast.'