RAIN GUAGE – device to measure precipitation

Homework Assignment #5

1. 
   Describe the conditions that are necessary for clouds to form.
   

2. 
   List the four processes of cooling that can lead to cloud formation. Define each.
   

3. 
   Compare cirrus, cumulus, and stratus clouds by completing this chart:
   

   Cloud	Altitude	Description of shape	Drawing of shape
   Cirrus
   Cumulus
   Stratus

4. 
   What kind of cloud causes thunderstorms?
   

5. 
   How are clouds and fog different?
   

6. 
   What instrument measures rainfall amount?
   

Thunderstorms

Lightning is a huge, hot spark of electricity that shoots out of a thunderstorm cloud. Thunder is the sound made when air heated by lightning explodes.

Caution: Lightning can be deadly. It is best to go indoors when lightning is nearby. If caught outdoors, stay away from high places and do not go under a tree. Crouch down on two feet, do not lie flat.

Light travels 186,000 miles per second, while sound travels only 1/5 of a mile per second. That is why you see the lightning before you hear the thunder. The farther away the lightning occurred, the more time elapses between seeing the lightning and hearing the thunder. It takes 5 seconds for thunder to travel one mile.

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  Flash Floods/Floods are the number one killer associated with thunderstorms with nearly 140 fatalities a year.
  
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  A thunderstorm is considered severe if it produces hail at least 3/4-inch in diameter, winds of 58 mph or higher, or tornadoes.
  

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  Severe Thunderstorms – long lived thunderstorms; formed in strong vertical wind shears; associated with gust fronts, high winds, and tornadoes
  
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  A severe thunderstorm watch is issued by the National Weather Service when the weather conditions are such that a severe thunderstorm is likely to develop.
  
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  A severe thunderstorm warning is issued when a severe thunderstorm has been sighted or indicated by weather radar. At this point, the danger is very serious and everyone should go to a safe place, turn on a battery-operated radio or television, and wait for further information
  
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  3 stages of thunderstorm development:
  
  1. 
     Cumulus - Warm humid air rises, cools, and condenses into cumulus cloud(s), Condensing water releases latent heat making cloud warmer than air around it. Insufficient time for precipitation to form. Updrafts keep water droplets and ice crystals suspended.
     
  2. 
     Mature - Cell = updraft + downdraft
     
  3. 
     Dissipating - Updrafts weaken and downdrafts dominate. Light precipitation, weaker winds
     
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  During a thunderstorm, positive and negative electrical charges build up in the clouds.
  
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  The discharge of the electricity between clouds is lightning.
  
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  Lightning is as hot as 30,000°C, hotter than the sun.
  
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  The heated air expands and explodes producing thunder.