Fronts Flashcards
What is the incline of a warm front typical
1:150
What speed does a pressure system typically move at
10-15knots
What speed does a warm front travel at
2/3 the speed of a polar front depression
What are the hazards of a warm front
Freezing rain in winter
Low cloud over large areas
Icing in cloud
Poor visibility in heavy rain / low cloud / fog
Aqua planing on wet runways
CAT around jet stream
What happens to pressure as a warm front approach’s
Pressure reduces
What happens to wind direction as a warm front approach’s
Wind veers
What is the slope of a cold front
1: 50
1: 80
What happens to pressure as a big CB passes over
Momentary drop in pressure
As a whole after cold front what happens to pressure
Increases
What clouds can be expected after a cold front
Surface heating
Cumulus clouds
Showers
Where does the jet stream appear to be on a surface weather chart
Appears:
50-200NM begins cold front
300-500NM infront of warm front
Where do clouds associated with a cold front usually occur
50-100nm after cold front
What are the hazards of flying in a cold front
Severe turbulence in CB cloud
Severe icing in CB cloud
Lighting from thunderstorms
Abrupt changes in wind direction passing through a cold front
Windshear associated with gust fronts and microbursts
Poor vis in heavy showers
CAT around a jet stream
Aquaplaning on we runway
What weather can be expected in the warm sector
Winter = stratus = drizzle, fog, stable
Summer = fair weather cumulus
What is a bent back occlusion
Where the occlusion has grown and then been “snapped back” by the low pressure
These have worse weather than normal occlusion
What are warm occlusion
When air is colder infront of the warm front than behind the cold front forcing the air behind cold front off the ground
What is a cold occlusion
When air is colder behind the cold front then air infront of warm front
Where does the rain fall in a warm occlusion
All rain falls infront of the surface position of the occluded front
Where does rain fall on w cold occlusion
Some rain falls behind surface position of occluded front but mostly ahead of surface position
What occlusion is normally doing in winter
Warm occlusion
Colder air to east because of European land mass cooling
What occlusion is usually found in summer
Cold occlusion
Air to west colder because of European land mass heating to east
What can be found in an occlusion that’s dangerous
Embedded CB
What is a polar air depression
Cold air over north polar waters
Moves south = goes over warmer oceans
= heats
=rises = depression
Winter only
What is a polar outbreak
When a polar air depression recedes but leaves a pocket of cold air over a warm area south
Stays aloft warm air
Won’t show on surface pressure chart
Shows as low pressure at altitude
What are the dimensions of a polar outbreak
300-700 miles
Can be From 10,000ft
Can last for several days
“Snow in Sahara”
What was established in 1952
World meteorological organisation (WMO)
What is the world meteorological organisation for
To standardise weather data collection
What happened in 1982
World area forecast system
What is the world area forecast system
World area forecast centres (sigwx charts)
Meteorological offices (TAF)
Meteorological watch offices (sigmet, airmet)
Meteorological stations
What direction does a non occluded frontal depression move
Direction of the top 2 isobars in the warm sector
