Chapter 13 The Nature of Storms

1. Average Number of Thunderstorm Days Annually… Florida is #1!!

2. Cause of Thunderstorms… Warm air rises over a mountain Temperature difference b/tw land & sea Fronts See next several slides for details, if desired!

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

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

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!

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

3. 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)

4. Lightning… 4. What is lightning?  A giant spark of static electricity How does a lightning bolt form?  A ‘-’ channel of air from a cloud (stepped leader) connects with a ‘+’ channel on the ground (return stroke).

Lightning… What causes thunder?  Super-heated air expanding and contracting How hot is lightning?  30,000 degrees Celsius

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

1. Tornadoes (Formation of…) A. change in wind direction & speed creates horizontal rotation. B. Strong updrafts tilt rotating air to vertical position. C. Tornado forms within rotating winds.

Tornado Alley The Midwest! 2. A supercell is a giant, self-sustaining storm that can spawn tornados. (A cP air mass from Canada meets a mT air mass from the Gulf of Mexico) 3. Tornado Alley is in the midwest. 4. Most tornadoes occur in May.

5. The Enhanced Fujita Scale… a. This scale is used to classify a tornado AFTER the tornado has passed by looking at the damage and effects of the tornado. b. EF0 to EF5

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

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

5c. The Enhanced Fujita Scale…EF4 or EF5 - Most dangerous!! - % of all tornados…  1 (Thankfully!) - Path…  50+ miles -Wind Speed…  200+ mph -Duration…  1+ hours

Tornado Safety… 1. Move to a pre-designated shelter – to a basement if possible. 2. Move to an interior room/hall, lowest floor, under sturdy furniture. (A bath tub is safest!) 3. Stay away from windows. 4. Get out of vehicles! 5. Don’t try to outrun a tornado. 6. If outside, lie flat in a ditch or depression. 7. Abandon a mobile home for a shelter.

Lesson 8 Tropical Storms & Hurricanes

Tropical Cyclones… 1. A tropical cyclone can be described as a…  Large, rotating, low pressure storm 2. We call these storms…  hurricanes 3. Tropical cyclones derive energy from…  Warm, tropical oceans

Tropical Cyclones… 4. Which direction do tropical cyclones turn in the northern hemisphere?  Counterclockwise  It is a low pressure system!  Remember the Coriolis effect? Fran, 1996, Cape Fear, NC Name was retired!

Tropical Cyclones… 5. As a hurricane strengthens, what do the following components do? a. Air pressure in eyewall– decreases b. Surface wind speeds – increase

Tropical Cyclones… 6. Tropical cyclones in the N. Hemisphere move steadily towards…  the west! 7. Which wind system moves across the USA and usually guides hurricanes out into the Atlantic Ocean?  the prevailing westerlies Hurricane Rita – 2005, 3 rd lowest pressure in Atlantic (897 mb), hit as cat. 3

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

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

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

Development of a Tropical Cyclone… Tropical Hurricane – pressure drops and the wind speeds reach 74 mph Ivan 2006 Dean 2007 Katrina 2005

Classifying Hurricanes… The Saffir-Simpson Scale 1. 4 characteristics of a hurricane described… a. Wind speed – how high? b. Air pressure – how low? c. Potential for damage – how much?! d. Storm surge

Classifying Hurricanes… 2. 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? a. Florida Keys, 1935 b. Camille, 1969 c. Andrew,

Classifying Hurricanes… 3. A hurricane runs out of energy When it moves over land or cold water

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

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

Storm Surge… a. 9 of every 10 people who die in a hurricane are killed by the storm surge. b. You should EVACUATE so you don’t get killed by the storm surge!

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

Hurricane Hazards… 4. Which agency is responsible for tracking and forecasting hurricanes?  The National Hurricane Center in Miami, FL (FIU Campus) (NOAA)

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

Lesson 9 Human Impact on Air Quality

Smog (Smokey Fog)… 1. Smog is a yellow-brown photochemical haze. 2. Smog is caused by solar radiation heating pollution (hydrocarbons & nitrogen oxides mostly from car exhaust). 3. Smog makes it difficult to breathe! 4. The major chemical in smog is ozone. b/c Ozone irritates the eyes, nose, throat, & lungs. See next slide…

Particulate Matter… 1. Four examples of particulate matter include… 1. ash, dust, pollen, & asbestos fibers. 2. These are forms of SOLID pollutants in the air. 2. Particulate matter is harmful to people because it can… get in lung tissues & cause breathing difficulties & lung disease. See next slide…

Review Only! 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!

Global Warming… 1. Global warming is… … an increase in Earth’s average surface temperature. 2. Some scientists believe that the cause of global warming is... … the burning of fossil fuels Write examples in margin… a. which releases carbon dioxide (CO2) b. CO2 makes up only.04% of the atmosphere! (4 out of 10,000 molecules) Coal for electricity Gasoline for vehicles Natural Gas for fireplaces and cooking

Add to Margin of Notes…Fossil Fuel Use Fossil Fuels Used… Coal for electricity Gasoline for vehicles Natural Gas for fireplaces and cooking 3. There are many scientists who believe the Sun has the major role in global warming/cooling. 4. To reduce levels of CO2 in the atmosphere people can … … reduce our use of fossil fuels! (And stop breathing!) How?

The Ozone Issue Review! The ozone layer is found in the stratosphere. 1. Ozone absorbs ultraviolet radiation from the sun.

The Ozone Issue 2. 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

The Ozone Issue 3. CFCs are used as refrigerants, coolants, propellants in aerosol cans, and Styrofoam. tiki.oneworld.net

Acid Precipitation (Rain)… 1. Acid precipitation (rain) is precipitation with a pH of less than 5. The pH of natural precipitation is 5.0 to Acid precipitation forms when sulfur dioxide (SO 2 ) & nitrogen oxides (NO 2 ) combine w/ atmospheric water to create sulfuric acid & nitric acid. 3. Six types of acid precipitation are acidic rain, snow, fog, mist, gas, and dust. 4. Nitrous oxide and sulfur dioxide come from volcanoes, marshes, and human activities

Acid Rain… 6. Three effects of acid precipitation are the damage it causes to… a. … aquatic ecosystems b. … plants & soil. c. … stone buildings & statues. Easy on the acid rain, guys!

Acid Rain… 7. Prevention: Use wet scrubbers on smoke stacks of coal-burning power plants. (to reduce sulfur emissions)