Download Chapter 13-Nature of Storms

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Chapter 13-Nature of Storms
Objectives:
1. Describe the life cycle of a thunderstorm and identify the processes that form thunderstorms. This
means I can:
a. List the 3 things required for a thunderstorm to form.
b. Explain the 3 stages of thunderstorm development in terms of updrafts and downdrafts,
cloud development, precipitation amount, etc.
c. Describe how latent heat causes clouds to continue to grow.
2. Compare & contrast different types of thunderstorms. This means I can:
a. Contrast the 2 main types of thunderstorms in terms of type of lift, what time of day they
usually occur, etc.
b. Explain what causes lift for mountain and sea-breeze subcategories of air mass
thunderstorms.
c. Identify what type of front causes the most severe thunderstorms and explain why.
3. Explain why some thunderstorms are more severe than others. This means I can:
a. Recognize the dangers of severe thunderstorms, including lightning, hail, high winds, and
floods.
b. Explain what causes lightning and thunder.
c. Explain why lightning occurs before thunder.
d. Differentiate between macrobursts and microbursts.
4. Describe how tornadoes form. This means I can:
a. Describe the steps of tornado development. (See Figure 13-8 p.338)
b. Identify the region of the US called “tornado alley”.
c. Identify the time of year that most tornados are likely to occur.
d. Explain what 2 types of air masses are usually involved in tornado formation.
e. List the characteristics used by the Fujita Intensity scale. I can determine the rank of a
tornado using the scale.
5. Identify where tropical cyclones originate. This means I can:
a. Analyze whether a tropical cyclone is likely to develop over a given area.
b. Identify the appropriate name for a tropical cyclone that develops in the Atlantic vs. the
Pacific.
c. Predict whether a storm is likely to increase or decrease in strength as it travels along a
given path.
6. Describe the life cycle of a tropical cyclone. This means I can:
a. Describe the time of year most tropical cyclones occur in the U.S. and explain why they are
more likely to occur then.
b. List the characteristics used by the Saffir-Simpson scale. I can determine what life cycle
stage or what level of hurricane a storm is using a given Saffir-Simpson scale.
c. List the 4 stages of hurricane development in order and know the basic characteristics of
each stage.
d. Label the eye and eyewall of a hurricane diagram.
7. Recognize the dangers of hurricanes. This means I can:
a. Describe where the winds are the strongest and the weakest.
b. Explain how a storm surge causes damage.
8. Describe recurring weather patterns, the problems they create and the atmospheric events that
cause them. This means I can:
a. Define heat wave, cold wave, drought, wind chill
b. Explain what type of pressure system is associated with droughts, heat waves, and cold
waves.
9. Additional miscellaneous vocabulary terms I can define, understand and use appropriately: SaffirSimpson, squall line, supercell, storm surge, dew point, wind shear, funnel cloud, downburst
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Section 13.1 Thunderstorms
3 Things Needed to Form a Thunderstorm
1. Abundant _________________ in the lower atmosphere
2. ______________mechanism
3. Atmosphere must be ______________ ; __________ with altitude, so air will continue to ______
Growth Limits Thunderstorms generally continue to grow until;
1. Meets air of __________________________________
2. Thunderstorms generally last ______________________
Classification of Thunderstorms
Thunderstorms are classified by type of __________________________________
1. Air Mass Thunderstorms
a. Due to _____________ surface heating throughout the ______________
b. Most common in _______________________
c. 2 subtypes
i. Mountain T-storms: ____________________ lifting
ii. Sea-breeze: temp differences between ____________________________
iii. See Fig 13-2 p.331
2. Frontal Thunderstorms
a. Steep front forces ____________ air ____ quickly
b. T-storm at ______________ edge
c. Normally produced by oncoming __________ fronts/ _______-pressure systems
d. Can last longer into the night
e. SOMETIMES produced by warm fronts, but not as often. Why not as often?
Stages of Development
T-storm Development – 3 stages classified by air movement _____________________
1. Cumulus stage
a. Air begins to ____________ vertically, creating ______________
b. __________________ transported to the ______________ levels of the clouds
c. Moisture _________________, at the top, releasing ____________________.
2. Mature Stage
a. ___________________________, cooling surrounding air
b. Cooled, ____________ air sinks to the ground with the rain, causing _______________
c. Equal amounts ______________________ and ________________ from
___________________ cells with ________________ winds.
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3. Dissipation Stage
a. ________________________ predominate
b. _______________ air predominates
c. Little ________________ air left, so no ________________________
d. “Dissipates”
Section 13.2 Severe Weather
1. Super Cells
a. Very powerful T-storms
b. Contain intense, rotating ______________________
2. Lightning
a. ________________________ caused by rapid rush of air in cumulonimbus cloud, due to
____________________ between ____________________ & ____________________
b. 30,000oC, __________ hotter than the ______________
c. ___________________ due to rapid expansion (_____________) and contraction of air
d. Lightning is _______________ than the speed of _____________. (See lightning_______
hear thunder.)
3. Wind
a. Downbursts: Violent ____________________ in a ____________________ area
I. Macrobursts: Destruction _____________ wide
II. Microbursts: Destruction less than ________ wide
4. Hail
a. Area of cloud with temperature ____________________________
b. Updrafts & downdrafts side-by-side
5. Floods
a. Usually occur when the upper winds are ___________ and push the storm ___________.
Therefore the rain stays longer over an area.
b. Rain falls faster than the ground can ________________ and faster than the streams can
________________.
6. Tornadoes
a. Violent, whirling, ________________ of air in contact with the ________________.
b. Prior to ground contact, there is a ___________________cloud.
c. Form when wind speed & direction ___________________________ with ____________.
d. Classification by Fujita Tornado Intensity Scale based on path _________, wind
_________ & _______________.
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e. Distribution
I. Occur most often in the ______________
II. Usually in the late _____________________________
III. _____________________ U.S. where cold _________ mass collides with _____
(________________ temp difference between 2 air masses.)
f.
Safety
Section 13.3 Tropical Cyclones
Tropical Cyclone
1. Large, rotating, _____________-pressure storms
2. Late summer & early fall
3. Called _____________________ in U.S. & Atlantic Ocean
4. Called _____________________ in the Pacific
5. Energy in a ______________ ocean AND the ______________ effect cause a cyclone rotation
with a _________________ spin (in _________________________ hemisphere)
a. _________, moist air ____________, then _______________, which releases _________
heat, and the rise continues!
i. Released heat causes continued rising, increased energy and increased spinning
speed.
b. Overall result:
i. ________ pressure in the cyclone center where air is rising
ii. Spiraling surface wind speed _________________
Tropical Cyclone Formation needs 2 things:
1. Abundant supply of ______________ water
2. Disturbance causing ___________
Tropical Cyclone Movement
1. Moves with ___________ currents
2. Lasts until no __________ ocean water energy is available to sustain it. Energy no longer
available when it reaches:
a. Land
b. Cold water
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Tropical Cyclone Stages:
1. Tropical Disturbance: Starts as a
a. ____________ low-pressure system, OR
b. Over the ITCZ (Intertropical Convergence Zone)
2. Tropical Depression has formed when _____________________ circulation around the lowpressure center occurs
3. Tropical Storm has formed when cyclonic winds around the center are ____________ or more
4. Hurricane has formed when winds are >= 120km/hr and the ______________ is present
a. The eye is ________________
b. The eyewall (band of wind around the eye) has the _____________ winds
Hurricanes-Miscellaneous
1. Classification: Based on wind speed & damage
2. Hazards: Violent winds of the _____________, storm surges & flooding, heavy __________
3. Advisories: tracking, forecasting, and issuing warnings 24 hours before the hurricane strikes
Section 13.4 Recurring Weather
1. Floods
2. Droughts
3. Heat Waves-usually accompany droughts
a. Winds blowing from the _______________ prevent __________ masses from moving in.
b. With a _________-pressure system there are no ______________, so the sun is intense.
c. Health problems
d. Heat Index: compares combined ____________________ & _______________ to the
body’s ability to __________ off.
4. Cold Wave
a. Also due to a ____________-pressure system, but with ________ air masses
b. Influenced by the __________________
c. Wind-chill factor: How __________ the air feels based on the estimated _______________
from skin due to ___________________ & _________
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Computer Review:
a. http://www.glencoe.com/sec/science/earthscience/index.html
b. Chapter Resources
c. Unit 4
d. Chapter 13
Bell work #1: Section 13.1
1. What 3 things are needed for a T-storm to develop?
2. When does a thunderstorm stop building?
3. Why are orographic and sea-breeze thunderstorms considered airmass storms rather than
frontal storms?
Bellwork #2 Weather Map, Predict & Explain:
1. Where Sunny?
2. T-Storms?
3. Wide Temps?
4. Where windiest?
Bellwork #2 Continued Weather Map, Predict:
1. Where Sunny?
2. T-Storms?
3. Wide Temps?
Bellwork #3 : Hurricanes
Prior Knowledge
1. Where do hurricanes most often occur?
2. What part of the hurricane is calm?
3. Where are the strongest winds?
Predict
4. What needs to be present for a hurricane to form?
5. What causes hurricanes to dissipate or lose energy?
Bellwork #4: Review Squall, etc.
1. What is a squall line?
2. What is the name or term for water pushed over the cost by a hurricane?
3. Can a tropical cyclone form over a hot desert? Explain.
4. Compare (tell a similarity) and contrast (tell a difference) between a mountain and a sea
breeze thunderstorm.
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