1. Chapter 13
The Nature of Storms

2. Lesson 7
Thunderstorms

3. Think About It…
During which months do we get the most damaging thunderstorms here in the Piedmont?

4. How do the major types of thunderstorms form?
Focus Question…
How do the major types of thunderstorms form?

5. Average Number of Thunderstorm Days Annually…

6. Types of Thunderstorms…
Air Mass - Mountain
Where… within one air mass over a mountain
Why… warm air rises over a mountain, forming storm clouds!
When… midafternoon

7. Types of Thunderstorms…
Air Mass - Sea-Breeze
Where… coastal areas, esp. tropics/subtropics
Why… temperature differences between land and sea create convection cells and updrafts
When… summer

8. Types of Thunderstorms…
Types of Thunderstorms…
Frontal - Cold
Where… at the leading edge of a cold front
Why… cold air pushes warm air rapidly up at the steep cold-front boundary
When… anytime a cold front moves in!

9. Types of Thunderstorms…
Frontal – Warm
Where… at the leading edge of a warm front
Why… warm air mass slides up over a cold air mass creating clouds
When… if a warm front moves in with enough moisture and instability

10. Thunderstorms in the Piedmont…
Which types of thunderstorms do we experience here in the Piedmont?
Frontal (warm and cold)
Local Air Mass (in the summer)

11. Stages of Development of a Thunderstorm…

12. NSSL – Q&A Thunderstorms…
The National Severe Storm Laboratory is in Norman, OK.

13. Severe Thunderstorms anvil Rain Free Base Precipitation

14. How Lightning Forms …

15. Lightning… A giant spark of static electricity
What is lightning?
A giant spark of static electricity
When does a lightning bolt form?
When there is an electrical imbalance between clouds (-) and the ground (+)
2a. What is a stepped leader?
An invisible channel of negatively charged air from a cloud

16. Lightning… 2b. What is return stroke (positive streamer)?
A channel of positively-charged ions from the ground
3. What causes thunder?
Super-heated air expanding and contracting
How hot is lightning?
30,000 degrees Celsius

17. Lightning Damage… 7500 forest fires/year 300 injuries/ 93 deaths/year
Lightning Damage…
The damage that lightning can do…
7500 forest fires/year
300 injuries/ 93 deaths/year
Property damage
Lightning-struck trees on the Blue Ridge Parkway

18. Lightning Q&A and Safety…

19. Lesson 8
Severe Weather

20. Where is the safest place to be during a tornado?
Think About It…
Where is the safest place to be during a tornado?

21. How do tornados form and how are they classified?
Focus Question…
How do tornados form and how are they classified?

22. The Fury of the Wind…
A downburst is a violent downdraft concentrated in a local area
Two types of downbursts are
macrobursts (more than 2 ½ miles wide / 130 mph winds / min)
microbursts (2 ½ miles wide / 168 mph winds / less than 10 min).
b. Microbursts are deadlier b/c they are hard to detect and plan for.

23. Hail… Precipitation in the form of balls or lumps of ice
2. What is hail?
Precipitation in the form of balls or lumps of ice

24. Floods…(The main cause of thunderstorm-related deaths)
What are 3 conditions that cause floods to occur?
Wind currents in the upper atmosphere are weak so that weather systems move slowly.
Abundant moisture over a limited area
Rain falls faster than the ground can absorb it.
ADD THIS  Groundwater levels are high and water can not infiltrate the ground.
Slide show May 17, 2011… The Flooding Mississippi River

25. Tornadoes (Formation of…)
A change in wind direction and speed creates a horizontal rotation.
Strong updrafts tilt the rotating air to a vertical position.
A tornado forms within the rotating winds.

26. Tornado Alley - The Midwest!
A cP air mass from Canada meets a mT air mass from the Gulf of Mexico forming a supercell.
A supercell is a giant, self-sustaining storm that can spawn tornados.
Most tornadoes occur in May.

27. The Enhanced Fujita Scale…
This scale is used to classify a tornado AFTER the tornado has passed by looking at the damage and effects of the tornado.

28. The Enhanced Fujita Scale…EF0 or EF1
- % of all tornados… 80
- Path…
up to 3 miles
- Wind Speed…
mph
- Duration…
1 – 10 minutes
Dr. Theodore Fujita

29. The Enhanced Fujita Scale…EF2 or EF3
- % of all tornados… 19
- Path…
15+ miles
- Wind Speed…
mph
- Duration…
20+ minutes

30. The Enhanced Fujita Scale…EF4 or EF5
- % of all tornados…
1 (Thankfully!)
- Path…
50+ miles
Wind Speed…
200+ mph
Duration…
1+ hours

31. Tornado Safety…
Move to a pre-designated shelter – to a basement if possible.
Move to an interior room/hall, lowest floor, under sturdy furniture. (A bath tub is safest!)
Stay away from windows.
Get out of vehicles!
Don’t try to outrun a tornado.
If outside, lie flat in a ditch or depression.
Abandon a mobile home for a shelter.

32. Lesson 9
Tropical Storms

33. From which direction do the hurricanes which hit our east coast come?
Think About It…
From which direction do the hurricanes which hit our east coast come?

34. How does a hurricane form?
Focus Question…
How does a hurricane form?

35. Tropical Cyclones… Large, rotating, low pressure storm hurricanes
A tropical cyclone can be described as a…
Large, rotating, low pressure storm
We call these storms…
hurricanes
3. Tropical cyclones derive a tremendous amount of energy from…
Warm, tropical oceans

36. Fran, 1996, Cape Fear, NC Name was retired!
Tropical Cyclones…
Which direction do tropical cyclones turn in the northern hemisphere?
Counterclockwise
It is a low pressure system!
Fran, 1996, Cape Fear, NC Name was retired!

37. Tropical Cyclones…
As a hurricane strengthens, what do the following components do?
Air pressure in eyewall– decreases
Surface wind speeds – increase
What are two basic conditions that tropical cyclones require to form?
Lots of warm ocean water
Disturbance to lift the air

38. Tropical Cyclones… the west! the prevailing westerlies
Tropical cyclones in the N. Hemisphere move steadily towards…
the west!
Which wind system moves across the USA and usually guides hurricanes out into the Atlantic Ocean?
the prevailing westerlies
Hurricane Rita – 2005, 3rd lowest pressure in Atlantic (897 mb), hit as cat. 3

39. Development of a Tropical Cyclone…
Tropical Disturbance – a weak, low-pressure system – group of thunderstorms collect

40. Development of a Tropical Cyclone…
Development of a Tropical Cyclone…
Tropical Depression – a disturbance begins to rotate around the center of low pressure
Katrina as a tropical depression

41. Development of a Tropical Cyclone…
Development of a Tropical Cyclone…
Tropical Storm – a depression is labeled a storm when the wind speeds reach 39 mph.
Tropical Storm Dalila, July 2007

42. Development of a Tropical Cyclone…
Development of a Tropical Cyclone…
Tropical Hurricane – pressure drops and the wind speeds reach 74 mph
Dean 2007
Katrina 2005
Ivan2006

43. Hurricane History…

44. Anatomy of a Hurricane…
Anatomy of a Hurricane…

45. Classifying Hurricanes…
1. What scale is used to classify hurricanes?
Saffir-Simpson
2. What are the four characteristics of a hurricane described by the scale?
Wind speed – how high?
Air pressure – how low?
Potential for damage – how much?!
Storm surge

46. Weds. 12/12/12…
2:10 pm
OVC St
46 degrees
30.26
54%
No fronts!

47. Classifying Hurricanes…
3. The Saffir-Simpson Scale…
Categories 1 – 5
Category that does the most damage – 5
Wind speed of a cat 5? > 155 mph
Three most powerful storms to hit USA?
Florida Keys, 1935
Camille, 1969
Andrew, 1992

48. Classifying Hurricanes…
4. A hurricane runs out of energy
When it moves over land
When it moves over cold water

49. Hurricane Hazards… 1. The strongest winds in a hurricane are in the…
… eye wall

50. Hurricane Hazards…
2. What is a storm surge?
When hurricane force winds drive a mound of ocean water towards coastal areas

51. Flooding from Hurricane Fran
Hurricane Hazards…
3. What hurricane hazard is caused by great amounts of rain?
floods
Flooding from Hurricane Fran

52. Hurricane Hazards…
5. Which agency is responsible for tracking and forecasting hurricanes?
The National Hurricane Center in Miami, FL at the FIU Campus (NOAA)

53. The World’s Best Hurricane Safety Tip…
EVACUATE!!

54. Human Impact on Air Quality
Lesson 10
Human Impact on Air Quality

55. Smog… Smog is a yellow-brown photochemical haze.
Smog is caused by the action of solar radiation on an atmosphere polluted with hydrocarbons and nitrogen oxides, mostly from car exhaust.
Smog can make it difficult to breathe!
The major chemical in smog is ozone.
Ozone irritates the eyes, nose, throat, and lungs.

56. Particulate Matter… Four examples of particulate matter include…
ash, dust, pollen, and asbestos fibers.
These are forms of SOLID pollutants in the air.
Particulate matter is harmful to people because they can…
lodge in lung tissues,
disrupt normal functions,
cause breathing difficulties and lung disease.

57. Global Warming… Global warming is…
an increase in Earth’s average surface temperature.
Some scientists believe that the cause of global warming is...
… the burning of fossil fuels
…which releases carbon dioxide (CO2)
Remember - CO2 makes up only .04% of the atmosphere! (4 out of 10,000 molecules)
There are many scientists who believe the Sun has the major role in global warming/cooling.

58. The Greenhouse Effect
What is the greenhouse effect? It is heat from the sun being trapped by the gases in our atmosphere.
A greenhouse effect you may relate to is that of a closed car on a cold, sunny day in winter.
The greenhouse effect is a GOOD thing! It allows for life on our planet!

59. The Greenhouse Effect

60. The Greenhouse Effect and Carbon Dioxide
news.bbc.co.uk
Carbon dioxide is released into the atmosphere by respiration, decay, and burning of fossil fuels. It is absorbed or stored by such carbon sinks as untapped fossil fuels, oceans, and forests.

61. The Ozone Issue The ozone layer is found in the stratosphere.
It absorbs ultraviolet radiation from the sun.

62. The Ozone Issue The ozone layer is important because…
Ultraviolet radiation from the sun can cause cataracts (a clouding of the lens of the eye) and skin cancer.
Ultraviolet radiation can kill the eggs of certain animals like amphibians because they lay their eggs in shallow water.

63. The Ozone Issue The chemical formula for ozone is O3 www.acd.ucar.edu

64. The Ozone Issue
Man-made chemicals called (CFCs) chlorofluorocarbons react with ozone and break it apart.
The part of the CFC molecule that reacts with the ozone molecule is the chlorine atom.
observe.arc.nasa.gov

65. The Ozone Issue
CFCs are used as refrigerants, coolants, propellants in aerosol cans, and Styrofoam.
tiki.oneworld.net

66. The Ozone Issue
This diagram illustrates what a “hole” in the ozone might look like.

67. The Ozone Issue
“The hole in the ozone layer above Antarctica is seen in a series of satellite images over a 21-year time span.
The hole may actually close within 50 years as the level of destructive ozone-depleting CFCs in the atmosphere is now declining, one of the world's leading atmospheric scientist Paul Fraser from the Australian government's Commonwealth Scientific and Industrial Research Organisation (CSIRO) said on Tuesday.
Fraser said he had measured a decline in ozone-destroying gases since — Reuters photo”

68. The Ozone Issue
d. CFCs were banned in the late 1980’s in industrialized nations. They are still in use in some places in the world.
“Under the 1987 Montreal Protocol, developing countries committed themselves to halving consumption and production of the CFCs by 2005 and to achieving an 85 percent cut by 2007.”

69. Acid Rain… Acid Rain is precipitation with a pH of less than 5.
The pH of natural precipitation is 5.0 to 5.6.
Acid precipitation forms when sulfur dioxide and nitrogen oxides combine with atmospheric moisture to create sulfuric acid and nitric acid.
Six types of acid precipitation are acidic rain, snow, fog, mist, gas, and dust.
Nitrous oxide and sulfur dioxide come from volcanoes, marshes, and human activities 69

70. Acid Rain…
f. The source of acid precipitation that receives the most attention is caused by coal-burning power plants in the midwestern USA.
Three effects of acid precipitation are...
It causes damage to aquatic ecosystems and vegetation.
It affects plants and soil.
It damages stone buildings and statues.
h. Acid precipitation can be prevented by using wet scrubbers to reduce emissions of sulfur dioxide by coal-burning power plants. 70

71. World’s Tallest Buddha…
Buddha will get a face lift after many years of weathering and acid rain damage.