1. Severe Weather DCI: 6.ESS2.6
Explain how relationships between the movement and interactions of air masses, high and low-pressure systems, and frontal boundaries result in weather conditions and severe storms.

2. Air Pressure & Weather
Cyclones and anticyclones are produced by differences in the air pressure around them.
A cyclone is created when areas of low pressure(warmer) surround it. Cyclones happen when air masses come together and rise.
**Meteorologists keep track and use these to predict the weather.
Turn to page 196. Look at the difference in how each moves.

3. Air Pressure & Weather
**Meteorologists keep track and use these to predict the weather.
Turn to page 196. Look at the difference in how each moves.

4. Air Pressure & Weather
An anticyclone is created in areas of high pressure (cooler). Anticyclones have denser air. The cooler, denser air moves out of the center of the high pressure area and move toward low pressure areas.
**Meteorologists keep track and use these to predict the weather.
Turn to page 196. Look at the difference in how each moves.

5. Air Pressure & Weather
**Meteorologists keep track and use these to predict the weather.
Turn to page 196. Look at the difference in how each moves.

6. What is Severe Weather?
Severe weather is weather that can cause property damage, injury and sometimes death.

7. Thunderstorms
Thunderstorms are small, intense weather systems that produce strong winds, heavy rain, lightening and thunder.
They usually occur along a cold front, but can also develop in other places.

8. Thunderstorms
There are only two atmospheric conditions required to produce a thunderstorm:
Warm and moist air near Earth’s surface
Unstable atmosphere
Unstable atmospheres happen when the surrounding air is colder than the rising air mass.

9. Lightning is an electric discharge that occurs between a positively charged area and a negatively charged area. It can happen between two clouds. Between Earth and a cloud, or even between two parts of the same cloud.
Thunder is the sound that results from the rapid expansion of air along the lightning strike.
Thunderstorms can produce one or more of the following conditions:
High winds, hail, flash floods, and tornadoes

10. A tornado is a small, spinning column of air that has high wind spends and low central pressure. In order to be considered a tornado, it must touch the ground. Otherwise, it is a funnel cloud.
A funnel cloud resembles a tornado, but it has not yet touched the ground. It is the beginning of a tornado.
Tornadoes

11. Hurricanes Hurricanes are the most powerful storms on Earth.
A hurricane is a severe storm that develops over tropical oceans and have strong winds that spiral in toward the intensely low-pressure storm center.

12. Hurricanes
A typhoon is a mature tropical cyclone (hurricane) that develops in the western part of the North Pacific Ocean between 180° and 100°E.

13. A hurricane begins as a group of thunderstorms.
Due to the Coriolis Effect, hurricanes spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
Eye Wall - surrounds the eye
Eye
Rain bands - produce heavy rains and high winds.

14. Hurricanes