1. I. Severe Weather Storms:
A. Thunderstorms:
1. Thunder Storms occur when warm, moist air moves upward rapidly, cools, condenses and forms cumulonimbus clouds.
2. These clouds are formed from strong updrafts caused by rapidly rising air.
3. As water drops become to heavy, they start to fall toward the ground.
4. The falling water causes strong downdrafts of wind.
5. The rapid updrafts & downdrafts build up electrical charges in the clouds.

3. 6. Some charges are positive and negative
7. When current flows between regions of opposite electrical charges, lightning flashes.
8. The resulting sound wave is thunder.

4. 1. Opposite charges attract.
B. What causes thunder and lightning?
1. Opposite charges attract.
2. Like charges repel.
3. Negatively charged bottom of Cb cloud attracts positively charged area or objects on the ground, as the attraction builds a connection can be made and the current will flow.
4. This is a lightning bolt.
5. Thunder results from the rapid heating of the air around the lightning bolt.
6. Lightning can reach temperatures of 30,000 degrees C.

5. 7. This extreme heat causes the air around lightning to expand rapidly.
8. After the lightning is gone the air cools and contracts.
9. This rapid motion of air particles cause sound waves called thunder.

6. 3. Causes an average of about 200 deaths per year.
C. Facts about thunder & lightning:
1. Lightning travels at the speed of light, so it is seen almost instantly. (300,000 km/s, 186,000 m/s)
2. Thunder travels at the speed of sound, so it takes longer to hear it. (1000 ft/s)
a.) 1 mile = approx. 5 seconds after lightning you will hear the thunder.
b.) 1 km = approx. 3 seconds after lightning you will hear the thunder.
3. Causes an average of about 200 deaths per year.

7. Ball lightning is a natural phenomenon, or debatably, a pseudoscientific theory. It is sometimes associated with thunderstorms. It takes the form of a long-lived, glowing, floating object, as opposed to the short-lived arcing between two points commonly associated with lightning. An early attempt to explain ball lightning was recorded by Nikola Tesla on March 5, 1904

8. Sheet lightning (heat lightning)
is real lightning, it's just far away. A thunderstorm dozens of miles away only spreads its flashes of light, not it's thunder, wind or rain. It's called heat lightning because it is on hot nights that small storms can kick up a windy, rainy fuss in one town and leave neighboring towns just viewing this heat lightning. But right underneath the storm, the lightning is called -- lightning -- and it can strikes a nearby tree with a tremendous clap of thunder. Miles away the same bolt is only seen as it back lights the side of a cloud
(hence the name sheet lightning)

10. The glow of lightning so far away, the thunder can not be heard.
4. Heat Lightning-
D. Things to Avoid:
1. Phones
2. TV
3. Taking Showers
4. Trees
5. Swimming Pools
6. Athletic Events (Ex. Golf, Baseball, etc.)

12. “Severe Weather II” I. Tornadoes:
A. What is a tornado?:
1. It is a violent funnel shaped wind storm that moves in a narrow path across land.
B. What causes tornadoes to form?
1. In very severe thunderstorms, the wind at different heights, blow in different directions, & at different speeds.
2. Wind Shear-
the difference in wind direction and wind speed.
3. Strong updrafts tilt the wind shear and produce rotation inside of the thunderstorm.

13. 4. This is when the funnel cloud starts to appear.
5. When it reaches Earth’s surface, they are called tornadoes.
C. Facts about tornadoes:
1. Internal winds can reach up to 500 km/hr or 300 mph.
2. Paths of tornadoes are irregular. The path can change at any time.
3. Width of a tornado can be from 100 meters wide to 600 meters wide. (Largest are about ½ -1 mile wide.)

14. 6. 3 out of every 4 tornadoes in the world occur in
4. Life span is usually less than one hour. (15 minutes on average)
5. Usually occur in the southwest corner of a low pressure system.
* Warm moist air and cold dry air meet and
form large thunderstorm cells.
6. 3 out of every 4 tornadoes in the world occur in
an area called Tornado Alley.

15. D. Tornado Classification:
1. We use the Fujita Scale to classify tornadoes.
F0 < 72 mph winds
F mph winds
F mph winds
F mph winds
F mph winds
F5 > 260 mph winds
2. Winds can’t be measured.
3. Damage is assessed to find the wind speeds.

16. II. Hurricanes:
A. What is a Hurricane?
1. A Hurricane is a very intense tropical low- pressure system that has winds of 74 mph (120km/hr) or more.
B. What causes the hurricane to form?
1. Wind from the southeast trade winds meet winds form the northeast trade winds.
2. These winds start to spin counterclockwise.
3. A low-pressure system forms in the middle of the spin
4. Air sinks in the center of this system.

17. 5. Outside of the center, warm moist air rises and forms clouds.
6. The center of the hurricane is called the eye of the storm. (high pressure)
7. Outside the eye is an area called the eye wall. (low pressure, most intense area of the storm)
8. When winds reach 74 mph, 120 km/h the storm is called a hurricane.
C. Facts about hurricanes:
1. They get their energy from the heat of the water.
2. Hurricanes weaken when they reach land or cold water.

18. 3. Wind speeds can reach 200 mph in the eye wall.
4. Most damage is not done by high winds or rain.
5. Storm Surge causes the most damage.
a.) can raise high tide feet.
b.) Causes extensive flooding.
c.) Drowning deaths.
d.) Building damage.
D. Hurricane Names:
1. Pre 1953 hurricanes were classified only by date.
only female names were used.

19. 3. 1979-present alternating male and female names are used
4. Names are recycled every six years.
5. Names of the strongest storms are retired from use.
6. A name is given to the storm after winds reach 65 mph.
7. A group of people develop a list to use each year.
8. The list is in alphabetical order. The first storm name starts with A.

20. Hurricane Names Selected for the Atlantic Basin
1997/2003
1998/2004
1999/2005
2000/2006
2001/2007
2002/2008
Ana
Alex
Arlene
Alberto
Allison*
Arthur
Bill
Bonnie
Bret
Beryl
Barry
Bertha
Claudette
Charley
Cindy
Chris
Chantal
Cesar
Danny
Danielle
Dennis
Debby
Dean
Dolly
Erika
Earl
Emily
Ernesto
Erin
Edouard
Fabian
Frances
Floyd*
Florence
Felix
Fran
Grace
Georges*
Gert
Gordon
Gabrielle
Gustav
Henri
Hermine
Harvey
Helene
Humberto
Horrtense
Isabel
Ivan
Irene
Isaac
Iris*
Isidore
Juan
Jeanne
Jose
Joyce
Jerry
Josephine
Kate
Karl
Katrina
Keith*
Karen
Kyle

21. Larry
Lisa
Lenny*
Leslie
Lorenzo
Lili
Mindy
Mitch*
Maria
Michael
Michelle*
Marco
Nicholas
Nicole
Nate
Nadine
Noel
Nana
Odette
Otto
Ophelia
Oscar
Olga
Omar
Peter
Paula
Phillippe
Patty
Pablo
Paloma
Rose
Richard
Rita
Rafael
Rebekah
Rene
Sam
Shary
Stan
Sandy
Sebastien
Sally
Teresa
Tomas
Tammy
Tony
Tanya
Teddy
Victor
Virginie
Vince
Valerie
Van
Vicky
Wanda
Walter
Wilma
William
Wendy
Wilfred
* Hurricanes retired since 1985.

22. Retired Names Since 1986 Retired Name Replacement Name Allison Andrea
Floyd
Franklin
Georges
Gaston
Iris
Ingrid
Keith
Kirk
Lenny
Lee
Michelle
Melissa

23. katrina

24. III. Blizzards:
A. What is a blizzard?
1. A snow storm that meets all of the following conditions is considered a blizzard.
a.) Wind speeds over 50 mph.
b.) Whiteout condition snow. (1/4 mile visibility.)
c.) Below freezing temperatures. (27 F. or lower.)

25. IV. Severe Weather Watches & Warnings:
A. The National Weather Service only issues watches and warnings.
B. What does a weather watch mean?
1. Means that severe weather is possible.
2. Be alert and listen for further reports.
3. Estimates of conditions are usually given.

26. C. What does a weather warning mean?
1. Means that severe weather has been sighted, detected in an area, or will be in an area soon.
2. Locations of the warning are given.
3. Direction of the storms should be given.
4. Probable conditions and intensity of the severe weather will be given.
5. Evacuations may occur in the strongest storms.