What is happens around fronts and how to storm systems form? A presentation for high school science.

1. WEATHER AROUND
FRONTS AND
CYCLOGENESIS

2. Weather Before
• Weather is influenced by the air mass over a region
• When a front begins to move over a region the weather
changes
• Once a front has moved pass a region the weather will
shift to the new air mass in place
• When a front approaches the pressure drops

3. Approaching Front
• Cold Front
• Rapid cloud development, cumulus and cumulonimbus.
• Heavy precipitation, over a short time
• In the Spring and Summer cold fronts will have thunderstorms,
some may be severe
• Front may pass through as fast as a few hours
• Warm Front
• Layered cloud development, cirrus clouds are indicators of an
approaching warm front
• Steady precipitation, over an extended time
• Front may take several days to pass through

4. Approaching Front
• Occluded Front
• Associated with large areas of rainy and severe weather
• This is part of a low pressure system
• Stationary Front
• Rainy weather around the front
• Passage may take several days because the front is not moving,
the front “stalls”

5. Behind the Front
• After a front passes the weather will change.
• After a cold front the:
• Temperatures are cooler
• Air is drier
• Pressure is higher
• After a warm front the:
• Temperatures are warmer
• The air is moist
• Pressure is higher

6. Wrap Up
• How does the weather change during and after a cold
front?
• What type of weather is associated with occluded and
stationary fronts?

7. Cyclogenesis
• Cyclogenesis is the development of a low pressure
system
• Low pressure systems in the middle latitudes are called
mid-latitude cyclones
• Mid-latitude cyclones usually develop along either the
polar jet stream or the sub tropical jet stream
• A mid-latitude cyclone goes through a life cycle of four
stages

8. Before the cyclone
• A stationary front forms a boundary between a cold and
warm air mass
• These fronts can be found along the jet stream

9. Stages of a cyclone
• Early Stage: A wave or “kink” in the front develops.
• The wave begins to rotate and the low pressure system is
born
• Precipitation begins to develop

10. Stages of a cyclone
• Open Stage: The drier, cooler, more dense air begins to
close in on the warm air.
• This stage the warm and cold fronts become easily
noticeable and more developed.

11. Stages of a cyclone
• Occluded Stage: The low pressure system becomes fully
developed.
• The cold front catches-up to the warm front and creates
an occluded front, this is part of the low pressure system.
• The storm is biggest in this stage

12. Stages of a cyclone
• Dissolving Stage: The occluded front becomes larger and
the supply of warm air is cut-off and pushed aloft
• The low-pressure begins to gradually dissipate

13. Wrap-up
• Draw in an L where the low pressure is
located.
• Draw in where the fronts are located.
• Which directions do all mid-latitude
cyclones move? Why?
• What stage is the cyclone in?