Air Masses

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Air Masses Fronts

• Types of Air Masses

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Air Masses
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Humidity

• Determined by the region an AIR MASS forms over
• If the AIR MASS forms over an ocean or large
  lake, it will be humid (maritime)
• If the AIR MASS forms over a land area, it will
  be dry (continental)

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Temperature

• If the AIR MASS forms at or near the equator, it
  will be warm (tropical)
• If the AIR MASS forms at or near the North or
  South Pole, it will be cold (polar)

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Polar Air Masses

• Cold, dense air has a higher air pressure
• Have high air pressure
• Are dense
• Usually dry because cold air cannot hold a lot of
  moisture

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Tropical Air Masses

• Warm, less dense air has a lower air pressure
• Are less dense than polar air masses
• Have low air pressure
• Usually humid because warm air can hold more
  moisture than cold air

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Connecticut Weather

• Influenced by maritime and tropical air masses
  that form over the Gulf of Mexico and the
  Atlantic Ocean
• Also, influenced by continental polar air masses
  from central and northern Canada which bring cold
  air to New England
• Weather along Long Island Sound usually more
  temperate because of our proximity to this large
  body of water

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Movement of Air Masses

• When an air mass moves into an area it interacts
  with other air masses causes the weather to
  change
• Air masses generally move WEST to EAST helped by
  the jet stream

• When 2 air masses meet, they do not mix easily
• The boundary where air masses meet is called a
  FRONT
• Storms and unsettled weather develop along FRONTS

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Types of Fronts

• Cold Front moves rapidly
• Warm Front moves slowly
• Stationary Front doesnt move
• Occluded Front

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Cold Front

• FAST cold air mass runs into SLOW warm air mass
• Cold air is dense sinks
• Warm air is less dense rises
• Warm air is pushed UP

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Cold Front

• Warm air can hold more moisture than cold air so
  clouds form
• Rain or snow may occur
• Cold fronts tend to move rapidly
• After they pass, cold, dry air moves in often
  accompanied by clear skies, a wind shift and
  cooler temperatures

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Warm Front

• FAST warm air mass overtakes a SLOW cold air mass
• Warm air moves atop cold air
• If the warm air mass is humid, light rain, snow
  will fall
• If the warm air mass is dry, cloudy weather occurs

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Warm Front

• Warm air fronts generally move slowly
• The weather may be rainy or snowy for several
  days
• After the warm front passes the weather will be
  warmer and more humid

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Stationary Front

• Occurs when a warm air mass meets a cold air mass
• The air masses are at a standoff
• Rain, snow, fog, clouds happen for long periods

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Occluded Front

• Happens when a warm air mass is trapped between
  two cooler air masses
• Complex weather system

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High and Low Pressure Areas

• HIGH pressure is usually accompanied by dry,
  clear weather
• LOW pressure is usually accompanied with clouds,
  wind, precipitation