Types of Severe WEATHER and Fronts

Objective:

Can I use meteorological data to predict weather?

Weather

A daily change in the condition of the atmosphere

Our Sun

The sun provides the

that is responsible for all of Earth’s weather

Types of weather

Severe weather

Tornado

• A severe storm that forms as rapidly rotating funnel cloud.

• The peak season in Tennessee is March – May

Tornadoes• Only happen in 1% of all

thunderstorms.• Small, spinning column of

air that has high wind speeds and low central pressure and that touches the ground.

• http://youtu.be/3Qu9wR03GVA

Formed from Cumulonimbus clouds

WEIRD SCIENCE• People have reported seeing “naked” chickens

after tornadoes strike rural areas. A likely explanation is that tornadoes cause chickens to shed their feathers, or molt. Chickens often molt when attacked. As the chickens molt, the strong tornadic winds blow their feather off.

Cool Facts

• About 75% of the world’s tornadoes occur in the US.

• Usually a tornado starts off as a white or gray cloud but if it stays around for a while, the dirt and debris it sucks up eventually turns it into black one.

• The United States have an average of 800 tornadoes every year .

• A Tornado in Oklahoma once destroyed a whole motel. People later found the motel’s sign in Arkansas.

Tropical Storms/Hurricanes

• Low pressure storm with high winds from the ocean

Categories of Hurricanes

1. 74-95 mph – minimal hurricane

2. 96-110 mph – moderate hurricane

3. 111-130 mph – extensive hurricane

4. 131-155 mph – extreme hurricane (Andrew)

5. >155 mph – catastrophic hurricane

Hurricanes

• Large, rotating tropical weather system.• It begins as a group of thunderstorms moving

over tropical ocean waters. • The source of energy is the evaporation of ocean

water.• As the warm, moist air rises, the water vapor

condenses and releases large amounts of energy.

• Catastrophic hurricane video:

Cool Facts:• Hurricanes are the most powerful storms on

Earth.• In the Pacific Ocean, Hurricanes are generally

known as typhoons. In the Indian Ocean they are called tropical cyclones.

• Hurricanes are the only weather disasters that have been given their own names.

• Hurricane season is from June to November when the seas are at their warmest and most humid, which are ripe conditions for a hurricane to develop.

Fronts• The point where two air masses meet

• Causes change in weather

Warm Front

• Warm air mass

• Will rise over cool air mass and gradually replaces the cold air.

• Cause light rain followed by hot humid weather

• A cold air mass

• Cold front will push under warm front

• Causes severe weather- heavy rains and thunderstorms

• Followed by cool weather

Cold Front

Occluded Front

• Forms when a warm air mass is caught between two colder air masses.

• Has cool temperatures and large amounts of rain and snow.

Stationary Front

• Forms when a cold air mass meets a warm air mass. Both air masses do not have enough force to life the warm air mass over the cold.

• Days of cloudy, wet weather.

Review Questions

1.Can you show me a cold front on this map?

2. Can you find a warm front on this map?

3. Can you find the occluded front on this map?

4. Can you find the stationary front on this map?

5.What type of weather is the northeast having?

6. Sharon woke up on a sunny morning and ate breakfast. Then she looked outside and saw tall, quickly-forming clouds. The clouds looked ready to rain. When she turned on the TV, she saw just what she thought--a forecast for sudden rains. What most likely caused the change in weather?

A. lack of wind

B. an expanding warm air mass

C. a warm front overtaking a cold air mass

D. a cold front overtaking a warm air mass

Storm Chasers

• http://ultimatechase.com/

Review:

1.What type of weather is the northeast having?

2. Sharon woke up on a sunny morning and ate breakfast. Then she looked outside and saw tall, quickly-forming clouds. The clouds looked ready to rain. When she turned on the TV, she saw just what she thought--a forecast for sudden rains. What most likely caused the change in weather?

A. lack of wind

B. an expanding warm air mass

C. a warm front overtaking a cold air mass

D. a cold front overtaking a warm air mass

3. If the wind was 135 mph what classification of hurricane would it be

4. Which of the following instruments measures air pressure?

a. thermometer

b. barometer

c. anemometer

d. windsock

5. On a summer evening, a barometer reading shows a gradual increase in air pressure. The humidity is 80%. The thermometer reading is slightly increasing. Based on these data, what type of weather should be expected for the next day? Why

Clear and Sunny

6. A student observes a clear sky and a temperature reading of 35 Celsius at 8:00 a.m. What is the most likely prediction about the day’s weather?

a. the day’s weather will be cold

c. the day’s weather will be hot

b. the day’s weather will be rainy

d. the day’s weather will be snowy

7. A meteorologist used radar to analyze the wind during a storm in the central plains of the United States. The winds were measured at 145 miles per hour and were moving in a circular pattern. According to the data, which event was the meteorologist most likely observing?

a. tornado c. rainbow

b. lightning storm d. cloud formation

• 8. “The weather tonight will be dominated by air movement that is caused by air moving from areas of high to low pressure.” This describes:

a. Blizzardb. Warm frontc. Tornadod. Wind

9. “Next week, you can expect this warm air mass to meet this cold air mass over the southern part of the state and bring rain and snow.” This best describes:

a. Cold frontb. Warm frontc. Occluded frontd. Stationary front

10. What type of weather will a warm front bring with it?

a. Cold and sunny

b. Cold and rainy

c. Cold and snowy

d. Sunny