Weather
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Transcript of Weather
WEATHER INTRODUCTION
This PowerPoint is designed to review different types of fronts and severe weather. Please view the PowerPoint in its entirety, as well as, completing the activity and quizzes, and viewing the simulation.
You may go back and review the PowerPoint at any time.
This is intended to help you with your Chapter 24 test.
TABLE OF CONTENTS
Fronts
Activity: Predicting the Weather
Quiz: Fronts
Severe Weather
Simulation: How Cumulus Clouds Form
Quiz: Severe Weather
WEATHER
According to Dictionary.com, weather is defined as “The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure.”
FRONTS
Density differences keep two air masses separate when they meet.
One air mass must collide with another air mass.
The kind of front that forms is determined by how the air masses move in relationship to each other.
TYPES OF FRONTS
Cold Front - The front edge of a moving mass of cold air that pushes beneath a warmer air mass like a wedge.
Warm Front – The front edge of advancing warm air mass that replaces colder air with warmer air.
Stationary Front – A front of air masses that moves either very slowly or not at all.
Occluded Front – A front that forms when a cold air mass overtakes a warm air mass and lifts the warm air mass off the ground and over another air mass.
SLOW MOVING COLD FRONT
Lifts warm air more slowly
Produces weaker storms
Produces lighter precipitation
FAST MOVING COLD FRONT
Clouds will form if the warm air is moist
Large cumulus and cumulonimbus clouds
Storms are usually short-lived and sometimes violent
Air behind cold front is noticeably colder and drier
WARM FRONT
Less dense warm air rises over the cooler air
Clouds may extend far ahead of the base of the front
Stratus clouds
Produces gentle precipitation over a large area
May cause violent weather
Air behind the warm front is warmer and more moist
COLD FRONT AND WARM FRONT
STATIONARY & OCCLUDED FRONTS
Stationary Front
Weather is similar to a warm front
Produces precipitation over a large area
May cause violent weather
Occluded Front
Wide variety of weather
Thunderstorms possible
Usually their passage is associated with a drying of the air mass
OCCLUDED FRONT
STATIONARY FRONT
PRACTICE PREDICTING THE WEATHER
Predict the WeatherDirections:1.) Click on the picture above2.) Once the webpage is open, click on “Predict the Weather”3.) Click on “Start Level 1”4.) Once you are finished with level one, bring me your computer so I can record your quiz score5.) Repeat for Levels 2 & 3
QUIZ: FRONTSCLICK ON THE CORRECT
ANSWER
1.) What is most likely to occur when a mass of cold air moves into a region occupied by warmer air?
A warm front will form, and there will be intense precipitation.
The air masses will mix rapidly, forming an air mass of intermediate temperature.
The boundary between the two air masses will be a zone of intense high pressure.
A cold front will form, as warm air is forced upward.
All of the above.
QUIZ: FRONTS
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QUIZ: FRONTS
GREAT JOB!
QUIZ: FRONTSCLICK ON THE CORRECT
ANSWER
2.) A front that is characterized by stratus clouds, and gentle precipitation for a long time is a(n) _______________ front.
cold
stationary
warm
occluded
none of the above
QUIZ: FRONTS
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QUIZ: FRONTS
Way to Go!
QUIZ: FRONTSCLICK ON THE CORRECT
ANSWER
3.) Storms along a cold front are usually short-lived and sometimes violent, while storms along a warm front
are short-lived and weak.
produce precipitation over a large area, and are sometimes violent.
are narrow, producing little rain and are always violent.
are long-lived, but always weak.
QUIZ: FRONTS
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QUIZ: FRONTS
Excellent!
QUIZ: FRONTSCLICK ON THE CORRECT
ANSWER
4.) A front that forms when a cold air mass overtakes a warm air mass and lifts the warm air mass off the ground and over another air mass is called a(n)
warm front.
stationary front.
occluded front.
cold front.
QUIZ: FRONTS
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QUIZ: FRONTS
Super!
SEVERE WEATHER
Severe Weather – weather that may cause property damage or loss of life.
This type of weather causes billions in damage each year
Sever Weather may include:
Large quantities of rain
Lightning
Hail
Strong Winds
Tornadoes
THUNDERSTORMS
Thunderstorm – a heavy storm that is accompanied by rain, thunder, lightning, and strong winds.
Thunderstorms develop in 3 stages
Cumulus Stage – warm, moist air rises, and the water vapor within the air condenses to form a cumulus cloud
Mature Stage – condensation continues as the cloud rises and becomes a dark cumulonimbus cloud
Heavy, torrential rain and hailstones may fall
Strong updrafts continue to rise, downdrafts form as air is dragged downward by the falling precipitation
Dissipating Stage – strong downdrafts stop air currents from rising
Thunderstorm dissipates as the supply of water vapor decreases
THUNDERSTORM CONT.
LIGHTNING
When clouds discharge electricity
Clouds must have areas that carry distinct electrical charges
Upper part of the cloud usually carries a positive charge
Lower part of the cloud mainly carries a negative charge
A huge spark travels within the cloud or between the cloud and ground to equalize electrical charges
LIGHTNING CONT.
TORNADOES
Tornado – a destructive rotating column of air that has very high wind speeds and that is visible as a funnel-shaped cloud
This is the most violent, and shortest-lived severe storm
Forms when a thunderstorm meets high-altitude horizontal winds
Horizontal winds cause the rising air to rotate
A storm cloud may develop a narrow, funnel-shaped, rapidly spinning extension that reaches downward
TORNADOES CONT.
Tunnel will move in a wandering, haphazard path if it touches the ground
Generally covers paths not more than 100 m wide
Usually, everything in that path is destroyed
Destructive power of a tornado is mainly due to the speed of the winds in the funnel
Winds may reach speeds of more than 400 km/h
Most injuries and deaths caused by tornadoes occur when people are trapped in collapsing buildings or are struck by objects blown by the wind
TORNADOES CONT.
HURRICANES
Hurricane – a severe storm that develops over tropical oceans and whose strong winds of more then 120 km/h spiral in toward the intensely low-pressure storm center
Warm, moist air over the ocean rises rapidly
Fully developed hurricanes consist of a series of thick cumulonimbus cloud bands that spiral upward around the center of the storm
Winds increase toward the center, or eye, of the storm and reach speeds of up to 275 km/h along the eyewall
The eye itself is a region of calm, clear, sinking air
HURRICANES CONT.
About 700 km in diameter
Most destructive storms that occur on Earth
Most dangerous aspect is rising sea level and large waves, called a storm surge
Every hurricane is categorized on the Saffir-Simpson scale by using several factors
Central pressure
Wind speed
Storm surge
Category 1 storms = least damage
Category 5 storms = catastrophic damage
HURRICANES CONT.
HURRICANES CONT.
Click on the picture below to see how cumulus clouds form
QUIZ: SEVERE WEATHER
CLICK ON THE CORRECT ANSWER
1.) The eye of the hurricane is a region of
hailstorms.
torrential rainfall.
calm, clear air.
strong winds.
QUIZ: SEVERE WEATHER
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QUIZ: SEVERE WEATHER
Exceptional!
QUIZ: SEVERE WEATHER
CLICK ON THE CORRECT ANSWER
2.) In the mature stage of a thunderstorm, a cumulus cloud grows until it becomes a
stratocumulus cloud.
altocumulus cloud.
cumulonimbus cloud.
cirrocumulus cloud.
QUIZ: SEVERE WEATHER
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QUIZ: SEVERE WEATHER
Out of Sight!
QUIZ: SEVERE WEATHER
CLICK ON THE CORRECT ANSWER
3.) What type of path does a tornado take if it touches down?
haphazard
extremely wide
straight
predictable
QUIZ: SEVERE WEATHER
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QUIZ: SEVERE WEATHER
Sensational!
QUIZ: SEVERE WEATHER
CLICK ON THE CORRECT ANSWER
4.) Lightning is caused by
heavy precipitation.
electrical differences within clouds or between the ground and a cloud.
thunder.
strong winds.
QUIZ: SEVERE WEATHER
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QUIZ: SEVERE WEATHER
Stupendous!
REFERENCES
Allison, M. A., DeGaetano, A. T., Pasachoff, J. A. (2008). Earth Science. Holt, Rinehart and Winston.
Bell, J., Prawat, R., et. al. A realist-constructivist approach to weather. (23 Feb., 2005). Retrieved April 19, 2010 from http://www.mltoolbox.org/wx/
Dictionary.com. (2010). Retrieved April 17, 2010 from http://dictionary.reference.com/browse/weather
Freedom Communications, Inc. “Occluded front.” Image. (2010). Retrieved April 19, 2010 from http://www.cbs6albany.com/images/research/Occluded_Schematic.JPG
Geography for kids, the study of our earth. “Stationary front.” Image. (1998). Retrieved April 20, 2010 from http://www.kidsgeo.com/images/stationary-front_sm.jpg
“Hurricane.” Image. Retrieved April 19, 2010 from http://blog.lib.umn.edu/olso4158/architecture/katrina-hurricane-pic3%5B1%5D.jpg
Impact Lab. “Tornadoes.” Image. (8 April 2009). Retrieved April 20, 2010 from http://www.impactlab.com/wp-content/uploads/2009/04/tornado.JPG
Mudra, P. “Squall line.” Image. (2010). Retrieved April 20, 2010 from http://www.bom.gov.au/weather/wa/sevwx/sevtspd.jpg
REFERENCES CONT.
Short, N. M. “Warm front.” Image. (2010). Retrieved April 19, 2010 from http://www.fas.org/irp/imint/docs/rst/Sect14/warmfront.jpg
UCAR Communications. “Thunderstorm.” Image. 2002. Retrieved April 19, 2010 from http://www.ucar.edu/communications/newsreleases/2002/thunderstorm.jpg
Van Dam, J. “Lightning.” Image. (2 June 2008). Retrieved April 20, 2010 from http://www.myscience.nl/wp-content/gallery/lightning/800px-lightning_strike_jan_2007.jpg
“Warm and cold front.” Image. (2006). Retrieved April 19, 2010 from http://www.suu.edu/faculty/colberg/Hazards/Weather/fronts1.jpg
Wheatley, G. EdHeads. (2000). Retrieved April 19, 2010 from http://www.edheads.org/
Wikipedia. (2 April 2008). Retrieved April 20, 2010 from http://en.wikipedia.org/wiki/Weather_front
Wikipedia. “Cold front.” Image. (2 April 2008). Retrieved April 20, 2010 from http://en.wikipedia.org/wiki/File:Example_of_a_cold_front.svg