NSF North Mississippi GK8

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Weather!

• Matt Aufman
• NSF North Mississippi GK-8
• November 2005

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Temperature

• You will usually see temperature measured in F
  for maps of the United States
• Maps of foreign countries will usually be
  measured in C

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Relative Humidity

• The relative humidity tells us how full the
  air is at the time of measurement.
• For example, 90 relative humidity means that at
  that moment the air is holding 90 of the maximum
  amount of water it could.

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Cloud Cover Symbols

• You will often see the circles drawn on a
  weather map

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High and Low Pressure Areas

• High pressure causes air to sink
• Usually results in several days of clear sunny
  skies

• Air rises in low pressure areas and forms water
  droplets
• Usually results in rain and storms

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Air Masses
There are two types of air masses 1.
Continental Polar air masses 2. Maritime
Tropical air masses
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Fronts
A front is the boundary separating air masses of
different densities

• Fronts extend both vertically and horizontally
  in the atmosphere

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Fronts Five Types of Fronts
1. Cold Front The zone where cold air is
replacing warmer air

• In U.S., cold fronts usually move from northwest
  to southeast
• Air gets drier after a cold front moves through

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Fronts Five Types of Fronts
2. Warm Front The zone where warm air is
replacing colder air

• In U.S., warm fronts usually move from southwest
  to northeast
• Air gets more humid after a warm front moves
  through

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Fronts Five Types of Fronts
3. Stationary Front When either a cold or warm
front stops moving

• When the front starts moving again it returns to
  either being a cold or warm front

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Fronts Five Types of Fronts
4. Occluded Front Formed when a cold front
overtakes a warm front

• This occurrence usually results in storms over
  an area
• In U.S., the colder air usually lies to the west

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Fronts Five Types of Fronts
5. Dry Line (Dew Point Front) Boundary
separating a dry air mass from a moist air mass

• This occurrence can result in tornadoes being
  formed
• Usually found in western part of U.S.

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Clouds Five Types of Clouds
1. High-Level Clouds Usually found at greater
than 20,000 ft.

• Usually made of ice crystals
• Examples include Cirrus, Cirrostratus

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Clouds Five Types of Clouds
2. Mid-Level Clouds Usually found between 6,500
and 20,000 ft.

• Usually made of water droplets, but can be made
  of ice
• Example is altocumulus

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Clouds Five Types of Clouds
3. Low-Level Clouds Usually found lower than
6,500 ft.

• Low, lumpy clouds that produce weak to moderate
  precipitation
• Examples include Nimbostratus and Stratocumulus

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Clouds Five Types of Clouds
4. Vertically developed These clouds are thick
and puffy and extend very far upwards

• Examples include Cumulonimbus and Fair Weather
  Cumulus
• Ordinary Cumulus clouds can quickly become
  Cumulonimbus clouds that start strong
  thunderstorms

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Clouds Five Types of Clouds
5. Other These are miscellaneous clouds

• These clouds do not really fit into any
  category, and all have different characteristics
• Examples include billow clouds, contrails,
  mammatus, orographic, and pileus

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Weather Maps Pressure Temperature
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Weather Maps Doppler Radar Maps
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Summary

• Temperature Usually in F, need to convert to
  C
• High pressure areas cause sunny weather low
  pressure areas cause rain and storms
• Two Types of air masses
• 1. Continental Polar
• 2. Maritime Tropical

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Summary (continued)

• Five types of fronts
• 1. Cold
• 2. Warm
• 3. Stationary
• 4. Occluded
• 5. Dew Point (Dry Line)
• Five types of clouds
• 1. High Level
• 2. Mid Level
• 3. Low Level
• 4. Vertically developed
• 5. Miscellaneous

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Sources
Palmer, Chad and Evans, David. May 20, 2005.
Occluded fronts can signal weakening of storm.
Accessed 28 October 2005. http//www.usatoday.com
/weather/tg/wofront/wofront.htm Palmer, Chad and
Kepple, Kevin. May 20, 2005. High-pressure
systems brings sunny days. Accessed 27 October
2005. http//www.usatoday.com/weather/tg/whighp/w
highp.htm Palmer, Chad and Kepple, Kevin. May
20, 2005. How low pressure systems affect
weather. Accessed 27 October 2005.
http//www.usatoday.com/weather/tg/wlowpres/wlowp
res.htm Weather World 2010, University of
Illinois. No date of publication given. Reading
and Interpreting Weather Maps. Accessed 21
October 2005. http//ww2010.atmos.uiuc.edu/(Gh)/
guides/maps/home.rxml