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The Nature of Storms. pics. Global Winds. H. jhhj. L. H. L. Local Winds. Wind directions change from day to night. Local Winds. Uneven Surface heat absorption/loss rates Surface °T differences lead to air °T & P differences High P Low P. air. air. Wind.
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The Nature of Storms pics
Global Winds H jhhj L H L
Local Winds • Wind directions change from day to night
Local Winds • Uneven Surface heat absorption/loss rates • Surface °T differences lead to air °T & P differences • High P Low P air air Wind Water Land Slow Heating/Cooling Fast Heating/Cooling
cumulonimbus Sea Breeze High P Low P Warm cold Sea Breeze Water Land
Land Breeze cumulonimbus High P Low P cold Warm Land Breeze Water Land
Review Local Winds • Land and Sea Breeze • Sea Breeze • Land Breeze
Mountain & Valley Breeze Cold Mountain Breeze Valley Breeze warm
Land, Water, and Air °T changes • Worksheet Graph & Qs. • Lab: Land, Water T absorption rates
Stages of Thunderstorm • Video time lapse thunderstorm
Stages of Thunderstorm • 1) Cumulus Stage • mT ~ Warm and Humid air • mT moves/rises/pushed up • Warm up drafts • Cumulus cloud forms Cumulus updraft updraft cP Warm Breeze cP mT
Stages of Thunderstorm Cumulonimbus • 2) Mature stage • mT ~ Up drafts • Cumulonimbus • Precipitation • Rain ~ cooling of air • down draft • Weaker up drafts Up draft Up draft Down draft Down draft Down draft Warmand cool Breeze Breeze
Stages of Thunderstorm • 3) Dissipation Stage • Clouds fall apart/sky clears up • No more precipitation • no warm updrafts • Only down drafts Down draft Down draft Down draft Cool/cold Breeze Breeze
Thunderstorms • Map of Thunderstorms cP mT
Stages of Thunderstorm • Video time lapse thunderstorm • Everyday weather thunderstorm 1/5 • HW thunderstorm
Features of Thunderstorms • lightning
Features of Thunderstorms • Lightning & Thunder • Light & Sound • Cumulonimbus up and down drafts • Friction between water/ice particles • Static electricity Build up & Discharge • Heated gas particles ~ plasma “glow” • Particles move apart quickly • Collision of particles ~ sound Up draft Down draft
Lightning Stepped leaders electrons Streamers +ions Return stroke
Lightning in cloud Cloud to cloud Cloud to ground
Lightning & Thunder • Light waves movefaster than Sound waves • 300,000 Km/s 0.33 Km/s Time lapse less distance/time more distance/time Sound Wave Sound Wave Light Wave
Lightning Safety • Lightning Safety
Lightning Safety • Highest location • Conductor materials • Water, R.H. • Outdoor sports/activity
Lightning Safety • safety
Dr. Megavolt • Lightning
Lightning • Roy Cleveland Sullivan (1912-1983) was a park ranger in Shenandoah National Park in Virginia. Between 1942 and 1977, Sullivan was hit by lightning seven times, which earned him an immortal place in the Guinness Book of World Records. • For this accomplishment, Sullivan was nicknamed “The Human Lightning Rod.” • Read more at http://www.environmentalgraffiti.com/news-man-who-was-stuck-lightning-seven-times#v4iZksxevYCWJgho.99
Lightning • Lightning
Lightning • Lightning has fascinated and excited humans for as long as they have watched the skies. Although meteorologists understand the cloud conditions necessary to produce it, lightning cannot be forecasted. At any moment, there are as many as 1,800 thunderstorms in progress somewhere on Earth, and each is producing deadly lightning. Lightning detection systems in the U.S. see an average of 25 million strokes of lightning each year, from some 100 thousand storms. It is estimated that the Earth is struck by 100 lightning bolts every second. • The clouds at the high levels of the thunderstorm are made of ice crystals. The formation of ice in a cloud is an important element in the development of lightning. Those storms that fail to produce large numbers of ice crystals may also fail to produce a lot of lightning. Strong rising and sinking motions within the cloud are important too, as they enhance collisions among cloud particles causing a separation of electrical charges. Positively charged ice crystals rise to the top of the thunderstorm and negatively charged ice particles and hailstones drop to the middle and lower parts of the storm. • As the differences in charges continue to increase, positive charges rise up taller objects such as trees, houses, and telephone poles. The charge can also move up you, causing your hair to stand on end! This is natures final way of warning you that lightning can strike near you very soon. • If the negatively charged area at the bottom of the storm gets large enough, sends out a channel toward the ground called a step leader. It is invisible to the human eye and moves in steps toward the ground. When the step leader nears the ground, or a target like a radio tower, it repels all the negatively charged in the surrounding area, and attracts all the positive charge. As the positive charges collect in high enough concentration, they send out small bolts of ground to air lightning called streamers. If the streamers can make contact with the step leader, an electric current wave propagates up the channel as a bright pulse -- lightning!
Features of Thunderstorms Nimbostratus Cumulonimbus
Features of Thunderstorms • Tornadoes • Land • Wave Cyclone • Cumulonimbus • Mature stage • Up and down drafts • Rotating air column • Vertical column • CCW rotation
Stages of a Tornado Tornadoes
Tornado Fujita Tornado Scale: F 0 - F 5 Wind speed ~ Max. 300 Km/hr Duration ~ min. – hr Path of Destruction ~ area • Tornadoes • Everyday weather part 3/5 Tornadoes cP Tornado Alley mT
Tornado • Path Prediction • Watch • mT and wave cyclone • Warning • tornado in the area
Tornado • SGCM: 13.2 Tornadoes
Features of Thunderstorms Hail & sleet mT Cumulonimbus Mature stage weak/no up drafts • Sleet • Hail • Weaker up drafts
Pressure Centers • NOAA Satellite • Cloud rotations ~ CCW & CW • Reasons
Pressure Centers H • Cyclone isolated Low pressure air mass Winds • CCW rotation • Toward the center L H H H
Pressure Centers L • Anticyclone isolated High pressure Winds • CW rotation • Away from the center H L L L
CLEAR SKY CLOUDS
Review Pressure Centers • NOAA Satellite • Lab Weather Map • “Wind Circulation around High & Low Pressure Centers.
Review Pressure Centers • NOAA Satellite • Lab Weather Map • “Wind Circulation around High & Low Pressure Centers. • Cyclone & Anticyclone wind rotation & direction
Pressure Centers • NOAA Satellite • CCW rotation • Cyclones over water • mT, Tropical Ocean ˃ 80 °F • June to November • Hurricane Katrina • Katrina, Sandy
Cyclone Speed H H H H H fast L slow L H H Wind speed difference of °T & P between air masses H
Cyclone • Higher °T/P difference = faster winds • Stages of Cyclone Formation • Tropical Disturbance: mT rising • Tropical Depression: winds ≤ 37 mph • Tropical Storm: winds 38-73 mph • Hurricane: winds ≥ 74 mph • Saffir-Simpson Scale ~ based on wind speed • C 1 - C 5 mT cP cP
Cyclone Hazards Hurricane Katrina 1) Wind Speed 74 mph 2) The Eye ~ calm center 3) Storm Surge ~ flooding Wind dragging water onto land