Transcript Air Pressure and Storms 3x

AIR
PRESSURE
Key Vocabulary:
-Air pressure
-High pressure system
-Low pressure system
-Wind
EQ: How does air pressure
affect the movement of air
masses?
Objective: Explain how air
masses move because of air
pressure differentials.
Final Exam
By the end of today’s lesson you will be able to correctly
answer the following question:
Which statement describes the general movement of air
masses?
A.
B.
C.
D.
They move from areas of high pressure to areas of low pressure.
They move from areas of high altitude to areas of low altitude.
They move from areas of low humidity to areas of high humidity.
They move from areas of low temperature to areas of high
temperature.
Final Exam
By the end of today’s lesson you will be
able to correctly answer the following
question:
Tornadoes can occur throughout the
United States. One area where most of the
tornadoes occur is known as Tornado Alley.
Which environmental factors most likely
impact the formation of tornadoes in this
area?
A. high pressure systems colliding with
other high pressure systems
B. cold dry air and warm dry air moving
towards each other
C. low evaporation rates and windy
conditions
D. cool dry air colliding with warm moist
air
Input
Make a list of where you’ve seen
hurricanes, thunderstorms, and
tornados in the media (TV shows,
movies, ect.)
How were these storms portrayed?
Which do you think is the most
dangerous?
QUICK REVIEW:
•
•
•
•
What are air masses??
How are air masses and fronts related??
What is high pressure and low pressure?
What type of weather do you get with high
pressure? Low pressure?
Draw a picture of what comes to your
mind when you think of the word
PRESSURE
What is
air
pressure?
Air pressure: the pressure
exerted by the weight of
air above it, is exerted in
all directions – down, up
and sideways
• Flow of air is caused by a
pressure difference between
two points
• Air or liquids move from areas
of high pressure to areas of
lower pressure
How do
air
masses
move?
Air masses move
from areas of high
pressure to areas of
low pressure
https://www.youtube.com/watch?v=jmQ8FWnM
0fA
What are
pressure
systems?
H’s and L’s on weather
maps (high or low)
• Center is the location of the
highest or lowest pressure in a
region
• The pressure differences
cause air to move in ways that
may make a high or low
become the center of a whole
system of weather
What are
highpressure
systems?
High-pressure system: formed
when air moves all the way
around a high-pressure center
• large, change slowly
Generally bring clear skies and
calm air/gentle breezes
• Air sinks to lower altitudes
and warms, which makes
clouds disappear
What are
lowpressure
systems?
Low-pressure system: large
weather system that
surrounds a center of low
pressure
• Forms as air moves around and
inward toward the lowest
pressure, and then up to higher
altitudes
• The upward motion of the air
lowers the air pressure further,
so the air moves faster
• Often forms between a warm
air mass and a cold air mass
• The rising air produces stormy
weather
What is
wind?
Wind is the result of
horizontal differences in
air pressure
• The unequal heating of Earth’s
surface (because of the axis tilt &
land/water heating differently!) generates
pressure differences
• Therefore, solar radiation is the
ultimate energy source for most
wind
Thunderstorm: a storm that
generates lightning and thunder and
frequently produce gusty winds,
heavy rain & hail
What is a
thunderstorm?
How do
thunderstorms
form?
Thunderstorms form when warm,
humid air rises in an unstable
environment (when air of different
densities is mixing)
Tornado: violent windstorm that
takes the form of a rotating column
of air called a vortex
What is a
tornado?
• Vortex extends down from a
cumulonimbus cloud during a t-storm
• Forms over land
• Can be up to a MILE wide
• Winds can reach up to 300 mph
Did Dorothy from the Wizard of
Oz live in a Tornado Alley?
Continental
Polar
Maritime
Polar
Maritime
Polar
Maritime
Tropical
Continental
Tropical
Maritime
Tropical
So what is tornado alley???
Continental
Polar
Maritime
Polar
Maritime
Polar
Maritime
Tropical
Continental
Tropical
Maritime
Tropical
Tornadoes form when a cP air mass
collides with a mT air mass (cool,
dry + warm, moist)
How do
tornadoes
form?
• Strong winds high up in the
atmosphere cause winds lower in the
atmosphere to spin, creating a vortex
Mesocyclone: vertical cylinder of
rotating air that develops in the
updraft of a thunderstorm
• only ½ of mesocyclones form
tornadoes
Hurricane: whirling tropical cyclone
winds of at least 119 km/hr that
forms over the ocean
What is a
hurricane?
• can be up to 600 miles across within
winds between 75– 200 mph!
• Each storm usually lasts for over a
week, moving over the open ocean
• HURRICANE KATRINA
Hurricanes gather heat and energy
through contact with warm ocean
waters
How do
hurricanes
form?
• Develop in the late summer, when
water temperatures are warm
enough to provide the necessary heat
& moisture to the air
The eye is the center of the
hurricane and is the calmest part
• The eye WALL is the harshest part of
the storm
Hurricanes only form over warm
ocean water -- 80°F or warmer.
How do
hurricanes
form?
• Therefore, hurricanes typically form
between 5 and 15° latitude N and S
(tropics)
• Meteorologists use water current and
temperature data to forecast
hurricanes
When they reach land, hurricanes
lose their strength without warm
ocean waters to fuel their energy
Compare and contrast highpressure and low-pressure systems.
Highpressure
systems
Lowpressure
systems
movement of air
large, change slowly
stormy weather
clear skies
forms between warm & cold air mass
forms
around pressure center
Final Exam
By the end of today’s lesson you will be able to correctly
answer the following question:
Which statement describes the general movement of air
masses?
A. They move from areas of high pressure to areas of low
pressure.
B. They move from areas of high altitude to areas of low altitude.
C. They move from areas of low humidity to areas of high
humidity.
D. They move from areas of low temperature to areas of high
temperature.
Final Exam
By the end of today’s lesson you will be able to correctly
answer the following question:
Which statement describes the general movement of air
masses?
A. They move from areas of high pressure to areas of low
pressure.
B. They move from areas of high altitude to areas of low altitude.
C. They move from areas of low humidity to areas of high humidity.
D. They move from areas of low temperature to areas of high
temperature.
Final Exam
By the end of today’s lesson you will be
able to correctly answer the following
question:
Tornadoes can occur throughout the
United States. One area where most of the
tornadoes occur is known as Tornado Alley.
Which environmental factors most likely
impact the formation of tornadoes in this
area?
A. high pressure systems colliding with
other high pressure systems
B. cold dry air and warm dry air moving
towards each other
C. low evaporation rates and windy
conditions
D. cool dry air colliding with warm moist
air
Final Exam
By the end of today’s lesson you will be
able to correctly answer the following
question:
Tornadoes can occur throughout the
United States. One area where most of the
tornadoes occur is known as Tornado Alley.
Which environmental factors most likely
impact the formation of tornadoes in this
area?
A. high pressure systems colliding with
other high pressure systems
B. cold dry air and warm dry air moving
towards each other
C. low evaporation rates and windy
conditions
D. cool dry air colliding with warm moist
air