Fronts and Frontal Depressions Flashcards
What is the polar front?
Where the polar and Ferrell air masses meet
What does cyclogenesis mean?
Describes the development of a low (depression)
What are the 6 stages of depression formation?
- Stationary front
- Frontal wave
- Open wave
- Mature
- Advanced occlusion
- Cut-off cyclone
What is a warm front?
Warmer air advancing on cold air
What is a cold front?
Colder air advancing on warm air
What is an occluded front?
Cold front rises or undercuts the warm front
What’s types of cloud are associated with a warm front?
Stratiform
What is the slop gradient of a warm front?
1:150
What is the speed of a warm front?
10kt
What are the flying hazards of a warm front?
- FZRA in winter
- Low cloud over large areas
- Icing in cloud
- Poor visibility in rain/low cloud/frontal fog
- Aquaplaning on wet runways
- CAT around jet stream
What happens as a warm front approaches?
Pressure reduces, lowering cloud with light rain
What happens at the warm front?
Rain and drizzle, pressure minimum, wind veers, increase in temp
What happens after the warm front?
Warm sector conditions, pressure slight increase
What are warm sector conditions?
Low cloud, intermittent drizzle, poor visibility, mild temp, potential for isolated Cb
What wind can you expect in the warm sector?
Geostrophic wind blowing parallel to the isobars
What clouds would you expect at a cold front?
Cumulus just ahead of the front
What is the cold front gradient?
1:50
How fast does a cold front move?
20-30kt
What are the flying hazards associated with cold fronts?
- Cb’s - turbulence, icing, lighting
- Wind shear - gust fronts and microbursts
- Poor visibility in heavy showers
- CAT around jet stream
- Aquaplaning on wet runways
What happens as a cold front approaches?
Slight pressure reduction
What happens at the cold front?
Heavy rain, minimum pressure, wind veers, decrease in temperature
What happens after the cold front?
Pressure increase, good visibility but isolated TCu/Cu
What weather would you find in an occluded front?
Combination of warm and cold sector weather
What is a warm occlusion?
When the cold air behind the occlusion is warmer than the air in front of the occlusion
What is a cold occlusion?
When the cold ai behind the occlusion is colder than the cold air in front of the occlusion
How is a warm occlusion shown on a weather chart?
As a continuation of the warm front
How is a cold occlusion shown on a weather chart?
As a continuation of the cold front
What isa stationary front?
Caused by the isobars being parallel to the warm/cold air boundary
What are the characteristics of the weather produced by a stationary front?
- Persists for several days
- Over a wide area
