Self-study Notes
Created by Chantelle B.
LPC (low pressure cell)
Mid- Latitude Cyclones
- LPC develops in the mid latitudes and travels WEST TO EAST
- Brings cold, windy, wet weather
- Winds blow around and into LPC ---> winds don’t blow straight along pressure gradient
- Occur over coastal areas and oceans
- Develop between 35oS and 70oS at polar front
- Cold fronts reach SA only in winter when pressure belts move slightly north
Southern hemisphere= clockwise
Northern Hemisphere= anti- clockwise
Coriolis Force: Forces that cause deflection of moving objects due to its rotation of Earth on its
axis ---> greatest at the poles
Pressure belt: bands of high/low pressure surrounding earth at certain latitudes
Effect of air masses on mid- latitude cyclones
- Happen 40o and 60o north and south of equator ---> where cold polar air meets
warm subtropical air in air mass zone called POLAR FRONT
- When air masses meet, warm air rises and cold air wedges underneath
- As it rises, warm air cools ---> condensation of water vapour occurs ---> produces
main weather characteristics of cyclone
- Cover areas between 1500km & 3000km in diameter
- Can move 1200km a day
- Lasts about 5 days
Conditions necessary for formation of mid- latitude cyclones
- POLAR FRONT ---> warm air mass is separated from cold air mass
- STEEP PRESSURE GRADIENT ---> variation of pressure between isobars
(the closer together, the steeper the pressure gradient)
Created by Chantelle B.
LPC (low pressure cell)
Mid- Latitude Cyclones
- LPC develops in the mid latitudes and travels WEST TO EAST
- Brings cold, windy, wet weather
- Winds blow around and into LPC ---> winds don’t blow straight along pressure gradient
- Occur over coastal areas and oceans
- Develop between 35oS and 70oS at polar front
- Cold fronts reach SA only in winter when pressure belts move slightly north
Southern hemisphere= clockwise
Northern Hemisphere= anti- clockwise
Coriolis Force: Forces that cause deflection of moving objects due to its rotation of Earth on its
axis ---> greatest at the poles
Pressure belt: bands of high/low pressure surrounding earth at certain latitudes
Effect of air masses on mid- latitude cyclones
- Happen 40o and 60o north and south of equator ---> where cold polar air meets
warm subtropical air in air mass zone called POLAR FRONT
- When air masses meet, warm air rises and cold air wedges underneath
- As it rises, warm air cools ---> condensation of water vapour occurs ---> produces
main weather characteristics of cyclone
- Cover areas between 1500km & 3000km in diameter
- Can move 1200km a day
- Lasts about 5 days
Conditions necessary for formation of mid- latitude cyclones
- POLAR FRONT ---> warm air mass is separated from cold air mass
- STEEP PRESSURE GRADIENT ---> variation of pressure between isobars
(the closer together, the steeper the pressure gradient)
