Severe Weather

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Severe Weather
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• Severe Weather
• There are many types including
• Lots of rain
• Lightning
• Hurricanes
• Hail
• Tornadoes
• Cyclones
• Blizzards

Questions List various forms of severe
weather.
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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• Thunderstorm
• Thunderstorm brief heavy storm with rain,
  thunder, lightning, and strong winds
• Stages
• 1. Cumulus stage warm air rises to form clouds
• 2. Mature stage the sever weather occurs
• 3. Dissipating stage storm decreases

Questions What is a thunderstorm? What are
the stages of a thunderstorm?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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• Lightning
• Lightning the discharge of electrical charges
• It occurs when ice and water in clouds rub
  together causes charges to build up
• Positive charges - at the top of cloud
• Negative charges - at the bottom of the clouds
• Too much builds up and the electrons travel to
  the ground
• As the electricity heats the air next to it, it
  expands quickly making thunder

Questions What is thunder and lightning and
how do they form?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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• Hurricanes
• Hurricane a tropical storm with winds are more
  than 74mph that spiral in toward the center
• Range from category 1 - 5
• How it forms
• Warm moist air over ocean rises and forms clouds
• Clouds rotate counter clockwise (in north)
• A low pressure forms in the center as the hot
  lighter air rises and pushes cold heavy air out
  of the way

Questions What is a hurricane and how does it
form?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
8

• Parts of the hurricane
• 3 layers of thick cumulonimbus clouds spiraling
  upward around the center
• The eye the center of the storm
• Calm and clear
• The eyewall part bordering the eye
• Highest winds are here

Questions What are the parts of a hurricane?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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Internal Hurricane Structure

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• Dangers of hurricanes
• Storm surge rising sea levels with large wave
• As air in center rises it pulls ocean water
  upward as it travels onto land it creates storm
  surges
• Wind damage determined by speed of wind, how
  buildings are constructed, etc.

Questions Explain the dangers of a hurricane.
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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• Cyclones
• Cyclone an area with low pressure that has
  winds moving toward the rising air in the center
  of an area
• Occurs in the mid-western US
• Also - what hurricanes are called in the Indian
  ocean

Questions What is a cyclone?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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• Cyclone formation
• 1. It starts where warm and cold air move
  parallel but in opposite directions
• 2. A piece of the cold front moves faster
  creating a wave
• 3. The fast moving cold overtakes the warm front
  and starts to spin

Questions Explain how a cyclone forms?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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http//esminfo.prenhall.com/science/geoanimations/
animations/Tornadoes.html
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http//www.bom.gov.au/lam/Students_Teachers/cycmod
.shtml
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• Tornadoes
• Tornado rotating column of fast moving wind
  that is visible a funnel shape
• Occur mostly in late spring and early fall
• Winds up to 400mph
• Formation
• 1. Hot dry air moves up and meets with cold air
  moving down
• 2. Air starts to spiral
• 3. It may develop a funnel shape
• If it does touch it wanders haphazardly and can
  rise and touch down again

Questions What is a tornado and how does it
form?
SC.912.E.7.6 Relate the formation of severe
weather to the various physical
factors. SC.912.E.7.8 Explain how various
atmospheric, oceanic, and hydrologic conditions
in Florida have influenced and can influence
human behavior, both individually and
collectively.
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How does the Enhanced Fujita Scale work? EF 0
Gale Tornado 65-85 miles per hour (mph) Some
damage to chimneys. Tree branches broken
off. Shallow-rooted trees uprooted. EF 1
Moderate Tornado 86-110 mph Roof surfaces
peeled off. Mobile homes overturned. Moving
autos pushed off roads. EF 2 Significant Tornado
111-135 mph Considerable damage. Roofs torn off
frame houses. Large trees snapped or uprooted.
Light object projectiles generated. EF 3 Severe
Tornado 136-165 mph Severe damage. Roofs and
some walls torn off well-constructed homes. Most
trees in forests uprooted. Heavy cars lifted off
ground. EF 4 Devastating Tornado 166-200
mph Well-constructed houses leveled. Structures
blown off weak foundations. Cars thrown and
large projectiles generated. EF 5 Incredible
Tornado 200 mph Strong frame houses lifted off
foundations and disintegrated. Automobile-sized
projectiles fly through the air in excess of 100
mph. Trees debarked.
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Blizzards
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Ice storms
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• Measuring weather in lower atmosphere
• We measure to try to predict future weather
  events
• Thermometers temperature
• Psychrometer humidity
• Barometer air pressure
• Anemometer wind speed
• Wind vein wind direction

Questions List the instruments used to
measure weather.
SC.912.E.7.5 Predict future weather conditions
based on present observations and conceptual
models and recognize limitations and
uncertainties of such predictions.
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Rain Gauge
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Hydrometer
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Mercurial Barometer
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Anemometer
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Wind vein
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• Measuring weather in upper atmosphere
• Radiosonde many instruments lifted by balloon
• Doppler Radar uses reflected radio waves to
  determine velocity and location of weather
• Weather satellites create images of weather
• Computers used for doing the math and store
  data for comparisons

Questions What instruments are used to
measure weather in the upper atmosphere?
SC.912.E.7.8 Explain how various atmospheric,
oceanic, and hydrologic conditions in Florida
have influenced and can influence human
behavior, both individually and collectively.
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Radiosonde
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Satellite
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Doppler Radar
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• Forecasting weather
• Use weather maps and models to put collected
  information in a picture
• To try to predict but - these are limited and
  not always accurate
• Map includes
• Have different symbols and colors to represent
  specific weather
• Have isotherms line connecting equal
  temperatures
• Have isobars lines connecting equal pressures

Questions What are used to forecast weather
and what are their limitation? What is the
difference between isobars and isotherms?
SC.912.E.7.5 Predict future weather conditions
based on present observations and conceptual
models and recognize limitations and
uncertainties of such predictions.
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Isotherms

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Isobars

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• Issuing weather alerts
• Watch when conditions are ideal for sever
  weather
• Warning when weather has been spotted

Questions What is the difference between a
watch and a warning?
SC.912.E.7.5 Predict future weather conditions
based on present observations and conceptual
models and recognize limitations and
uncertainties of such predictions.
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• Trying to control the weather
• Used techniques like cloud seeding
• Cloud seeding process of introducing
  condensation or freezing nuclei into a cloud to
  force precipitation
• Purpose either increase rain, decrease rain,
  reduce lightning
• It did not work
• Still are working on it to try to improve the
  process

Questions What is cloud seeding, why is it
used, and what are the results?
SC.912.E.7.5 Predict future weather conditions
based on present observations and conceptual
models and recognize limitations and
uncertainties of such predictions.