Quiz

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Quiz

• Write an exam question related to this past
  week's material.
• worth 2-4 points
• any format you like
• moderately difficult
• more than a simple factual question (e.g. "what
  is the atmosphere composed of?" bad question).
• Provide an answer key.
•  
• You'll be graded on the quality and relevance of
  your question, as well as the accuracy of your
  answer.

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All questions submitted will be considered for
inclusion on the next exam. Selection for
inclusion will be rewarded with up to 5 extra
credit points.
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Weather

• (movie)

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Air Masses

• What is an air mass?
• regional, homogeneous masses of air having
  specific conditions of temperature, humidity, and
  stability
• How do they form?
• By remaining stable over a source region long
  enough to take on specific characteristics
• How are they modified?
• migrate from source region, take on
  characteristics of new location.

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Air Masses Winter
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Whats stability?

• A characteristic of parcels within an air mass
• Refers to the tendency of an air parcel to either
  remain in place vertically or change
• Depends on the temperature and moisture
  conditions within the parcel.

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Whats stability?

• There are three options
• Stable
• resists change in vertical position
• parcel is same temperature/humidity as
  surrounding air
• Unstable
• parcel is warmer than surrounding airwill rise
• Conditionally unstable
• cooler than surrounding air if unsaturated
  (stable)
• warmer than surrounding air if it reaches
  saturation (unstable)

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Air Masses Summer
Fig 8-5
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OK. We have air masses. How do we get weather
(precipitation)?

• We need to cool the air mass to saturation

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How do we do that?

• We need a Lifting Mechanism.
• What are the Big 4 LMs?
• Convergent, Convectional, Orographic, and Frontal

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(No Transcript)
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Convectional
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Convergent
Fig 8-5
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Orographic
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Fig 8-8
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Frontal
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Have a Good Weekend