Weather Vocabulary

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Weather Vocabulary
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Weather

• The happenings in the atmosphere at a certain
  time.

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Global Pattern

• A global pattern is something that affects the
  entire world. It is a pattern that is seen
  throughout the world.
• Weather patterns are examples of global patterns.
  Climate has global patterns.
• These are systems that are important because
  they affect our entire planet.

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Atmospheric Movement

• This is the large scale movement of air
  throughout the atmosphere.
• This movement, by air currents, is how heat is
  distributed all over our planet.

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What are Air Masses????

• Large areas (blobs) of air that have the same
  weather, temperatures and humidity
• Weather changes occur with changes in air masses

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High Pressure System

• In a high atmospheric pressure system the
  atmospheric pressure of the air is higher than
  that of the air around it. (Its less dense)
• High atmospheric pressure systems are marked by
  an H on a weather map
• They mean clear weather.

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Low Pressure System

• In a low atmospheric pressure system the
  atmospheric pressure of the air is lower than the
  air around it. The air is more dense.
• Low atmospheric pressure systems are symbolized
  by an L on a weather map.
• They mean storminess and precipitation

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Front- This term is not on your vocabulary page.
However, you should add it and are expected to
know the definition

• A place where two air masses of different
  temperatures meet.

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What Do Fronts Do???

• They bring changes in the weather
• (from west to east)
• Fronts are named for the air that is behind them

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Cold Front

• Cold dense air pushes warm air out of the way
• Cold fronts move very quickly and bring short
  periods of rain/thunderstorms
• Lower temperatures are behind the front
• SYMBOL the direction of the arrows points
  towards the direction the front is MOVING

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Cold Front Diagram
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Warm Front

• Warm air moves up the cold front as it slowly
  displaces the cold air
• Warm fronts move slowly, and bring many days of
  steady precipitation
• Higher temperatures are behind the front
• SYMBOL direction of half-moons is the
  direction the front is moving

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Stationary Front

• The air from the warm front and cold front meet,
  but do not move
• These fronts have the same weather as warm fronts
  
• SYMBOL warm and cold fronts are moving in
  opposite directions, thus making a stationary
  condition

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Occluded Front

• An occluded front is a weather pattern. It
  happens when a cold front overtakes a warm front
  capturing the warm air between two cold air
  masses.
• Usually produce light rain or other precipitation

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Lets see it on the map!
Stationary Front
Cold Front
Warm Front
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What is El Niño ?

• El Niño is an abnormal warming of surface ocean
  waters in the eastern tropical Pacific.

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Normal Conditions
Strong winds blow from the east along the
equator, pushing warm water into the Pacific
Ocean
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Normal Conditions

• The different water temperatures of these areas
  effects the types of weather these two regions
  experience.
• In the east the cool water cools the air above
  it, and the air becomes too dense to rise to
  produce clouds and rain.
• In the western Pacific the air is heated by the
  water below it, increasing the buoyancy of the
  lower atmosphere thus increasing the likelihood
  of rain.
• This is why heavy rain storms are typical near
  Indonesia while Peru is relatively dry.

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El Niño Conditions
An El Nino condition results from weakened trade
winds in the western Pacific Ocean near
Indonesia, allowing piled-up warm water to flow
toward South America.
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El Niño Conditions

• This flattens out the sea level, builds up warm
  surface water off the coast of South America, and
  increases the temperature of the water in the
  eastern Pacific.

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El Niño Conditions

• What happens to the ocean also affects the
  atmosphere.
• Tropical thunderstorms are fueled by hot, humid
  air over the oceans.
• The hotter the air, the stronger and bigger the
  thunderstorms.
• As the Pacific's warmest water spreads eastward,
  the biggest thunderstorms move with it.

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El Niño Conditions

• The clouds and rainstorms associated with warm
  ocean waters also shift toward the east.
• So, rains which normally would fall over the
  tropical rain forests of Indonesia start falling
  over the deserts of Peru, causing forest fires
  and drought in the western Pacific and flooding
  in South America.

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El Niño Conditions

• The Earth's atmosphere responds to the heating of
  El Niño by producing patterns of high and low
  pressure which can have a profound impact on
  weather far away from the equatorial Pacific.
• For instance, higher temperatures in western
  Canada and the upper plains of the United States,
  colder temperatures in the southern United
  States. The east coast of southern Africa often
  experiences drought during El Nino.

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Thunderstorms

• Small area storms formed by the strong upward
  movement of warm, moist air
• Usually occur ahead of a cold front as the
  colder, denser air shoves the warmer air upward
• This movement of air forms the cumulonimbus
  clouds that produce thunderstorms
• These storms are accompanied by heavy rain,
  thunder, lightning, sometimes hail, and can also
  produce tornadoes

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• All thunderstorms produce lightning
• Lightning is the discharge of huge amounts of
  static electricity (think of walking across a
  carpet in your socks and then touching
  something-ZAP)
• Thunder is the result of the air quickly
  expanding from the heat of the lightning bolt
• You cannot have lightning without thunder!!

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Thunderstorm formations Form SEVERE storms and
tornadoes! THIS IS ONE BIG STORM SYSTEM!
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Tornadoes

• Form from very powerful thunderstorms
  (cumulonimbus clouds)
• These are funnel shaped columns of spiraling
  winds that extend down to the ground from the
  base of a cloud
• The winds move into a tornado (low pressure), and
  can reach a maximum of 318 mph!
• Spin COUNTER CLOCKWISE (like a hurricane)
• The actual funnel is made by water droplets
  (clouds) and dust

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TROPICAL STORMS
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HURRICANES
Hurricanes are tropical storms where the winds
get faster than 118 km/h (73 mph). The storms
have a central area of calm known as the "eye",
which is the funnel through which the warm air
rises.
Why are we seeing more of these destructive
storms?