Download Chapter 13 Weather

Chapter 13 Weather
S6E4-Understand how the distribution of land and
oceans affects climate and weather.
E.Q.: How do scientist describe and predict weather?
Lesson 1: Describing Weather
• What is weather?
• http://pmm.nasa.gov/e
ducation/videos/nasaour-world-whatweather
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• Weather is the
atmospheric condition,
along with short-term
changes, of a certain
place at a certain time.
• In other words our
weather outside is not
the same as the
weather in Florida right
now.
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Lesson 1: Describing Weather
Weather Variables
• Meteorologist use • air temperature
• air pressure
several variables
• wind speed and
to predict the
direction
weather.
• Humidity
• cloud coverage
• precipitation.
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Lesson 1: Describing Weather
• Air Temperature
• The measure of kinetic
energy or movement of
molecules in the air.
• Air temperatures vary
with time of day,
season, location, and
altitude.
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Lesson 1: Describing Weather
• Air Pressure
• http://www.watchknow
learn.org/Video.aspx?Vi
deoID=8286&CategoryI
D=7316
• The force a column of
air applies on the air or
a surface below.
• Air pressure decreases
as altitude increases.
• Also referred to as
barometric pressure.
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Lesson 1: Describing Weather
• Wind
• As air moves from areas of
high pressure to areas of
low pressure, it creates
wind.
• Wind is named by the
direction it blows from.
Westerlies flow from west
to east.
• An anemometer measures
wind speed.
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Lesson 1: Describing Weather
• Humidity
• The amount of water vapor
in the air.
• When the humidity is high
there is more water vapor in
the air.
• High humidity might make
your skin feel sticky or
sweat might not evaporate
as quickly.
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Lesson 1: Describing Weather
• Relative Humidity
• The amount of water
vapor in the air
compared to the
maximum amount of
water vapor the air
could hold at a certain
temperature.
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• Like a sponge, air can only
hold so much water vapor.
• Temperature determines
the amount of water vapor
air can hold.
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Lesson 1: Describing Weather
• Dew Point
• The temperature at which
air is staturated and
condensation can occur.
• If the temperature is above
0º C, dew forms.
• If the temperature is below
0º C, frost forms.
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Lesson 1: Describing Weather
• Clouds and fog
• Clouds are water droplets or
ice crystal suspended in the
atmosphere.
• A cloud that forms near
Earth’s surface is fog.
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Lesson 1: Describing Weather
Precipitation
• Water in liquid or solid
form, that falls from the
atmosphere.
Type of Precipitation
• Rain
• Snow
• Sleet
• Hail
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Lesson 1: Describing Weather
• The Water Cycle is the
series of natural
processes by which
water continually
moves among oceans,
land, and the
atmosphere.
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Lesson 1: Describing Weather
Show what you know!
1. What is weather?
2. What variables are used to describe
weather?
3. How is weather related to the water cycle?
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Lesson 2: Weather Patterns
What is a high pressure system?
• A whirling mass of cool, dry air that generally brings
fair weather and light winds.
• When viewed from above, winds spiral out of a highpressure center in a clockwise rotation in the
Northern Hemisphere. These bring sunny skies.
• A high pressure system is represented as a big, blue
H.
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Lesson 2: Weather Patterns
What is a low pressure system?
• A whirling mass of warm, moist air that generally
brings stormy weather with strong winds.
• When viewed from above, winds spiral into a lowpressure center in a counterclockwise rotation in the
Northern Hemisphere.
• A low pressure system is represented as a big, red L.
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Lesson 2: Weather Patterns
•
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Lesson 2 Weather Patterns
• What is an air mass?
An air mass is an extremely large body of air
whose properties of temperature and
moisture content (humidity), at any given
altitude, are fairly similar in any horizontal
direction.
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Lesson 2 Weather Patterns
• Air masses cover large (hundreds of miles)
areas.
• Air masses control the weather for a relatively
long time period: from a period of days, to
months.
• Most weather occurs along the periphery of
these air masses at boundaries called fronts.
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Lesson 2 Weather Patterns
• There are 4 general air mass classifications
categorized according to the source region:
• Polar
• Tropical
• continental
• marine
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Lesson 2 Weather Patterns
• There are 4 general air mass classifications
1.) Polar latitudes (P) - located poleward of 60 degrees
north and south
2.) Tropical latitudes (T) - located within about 25
degrees of the equator
3.) Continental (c) - located over large land masses, dry
4.) Marine (m) - located over the oceans
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Lesson 2: Weather Patterns
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Lesson 2 Weather Patterns
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Lesson 2 Weather Patterns
What is a front?
• A front is a boundary between two different
air masses, resulting in stormy weather.
• A front usually is a line of separation between
warm and cold air masses.
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Lesson 2 Weather Patterns
• Cold front-colder air mass moves toward a
warmer air mass.
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Lesson 2 Weather Patterns
• Warm fronts-warmer air moves towards
cooler air.
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Lesson 2 Weather Patterns
• Stationary front-stalls for several days with
warm air on one side and cold on the other
side of it.
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Lesson 2 Weather Patterns
• Occluded fronts-when a fast moving cold
front catches up to a slow moving warm
front. Usually brings precipitation.
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Lesson 2 Weather Patterns
• Some weather events can cause damage,
injuries, and even deaths.
• These events are referred to as severe
weather.
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Thunderstorms
Also known as
electrical storms
because of their
lightening.
• https://www.youtube.com/
watch?v=IatoWCinM9w
3 Stages of a
thunderstorm
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Tornadoes
A violent whirling,
whirling column of air
in contact with the
ground.
• http://video.nationalgeogr
aphic.com/video/101videos/global-warming101?source=relatedvideo
• https://www.youtube.com/
watch?v=gieSbj2svwY
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Hurricanes
An intense tropical
storm with winds
exceeding 119 km/h
or around 74 mph.
http://www.pbslearningmedi
a.org/resource/ess05.sci.es
s.watcyc.hurrlife/howhurricanes-form/
https://www.youtube.com/w
atch?v=a-SnxC-BkPo
http://www.accuweather.com/en
/weather-video/video-inside-ahurricaneseye/1116007390001
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Winter Storms
Winter weather can
also be severe. Snow
and ice can make
driving dangerous.
A blizzard is a violent
winter storm with
freezing temperatures,
strong winds, and
blowing snow.
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Lesson 2 Weather Patterns
• The U.S. Weather
Service issues watches
and warnings during
severe weather.
• It is important to know
how to protect yourself
during dangerous
weather.
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• During thunderstorms,
stay inside and away
from metal objects and
electrical cords.
• If outside, stay away
from water, high places,
and isolated trees.
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Lesson 2: Weather Patterns
Show What You Know!
1. What are two types of pressure systems?
2. What drives weather patterns?
3. Why is it useful to understand weather
patterns?
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Lesson 3: Weather Forecast
Measuring the weather
• Meteorologist use
specialized instruments
to measure conditions
in the atmosphere.
• ThermometerTemperature
• Barometer-Air Pressure
• Psychrometer-Relative
Humidity
• Anemometer-Wind speed
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Lesson 3: Weather Forecast
• Surface report
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• Describes a set of
weather measurements
made on Earth’s surface.
• Weather variables are
measured by a weather
station, (a collection of
instruments that measure
temp, air pressure,
humidity, wind,
precipitation, and cloud
amounts.
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Lesson 3: Weather Forecast
• Upper-air report
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• Describes wind,
temperature, and humidity
conditions above Earth’s
surface.
• Measured by radiosonde,
(weather instruments
carried many km above
ground by a weather
balloon)
• Reports are made twice a
day at hundreds of locations
around the world.
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Lesson 3: Weather Forecast
Satellites
• Meteorologist use
visible light and infrared
satellite images to
identify fronts and air
masses.
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Lesson 3: Weather Forecast
Doppler Radar
• A specialized type of
radar that can detect
precipitation as well as
the movement of small
particles, which can be
used to approximate
wind speed.
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Lesson 3: Weather Forecast
Weather Maps
• Station Model-displays
data from different
measurements for a
particular location.
• Isobars are lines that
connect all places on a
map where pressure
has the same value.
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Lesson 3: Weather Forecast
Predicting the Weather
• Meteorologists analyze
data from various
sources, such as radar
and computer models
to prepare forecasts.
• Computer models are
detailed computer
programs that solve a
set of complex math
formulas.
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Lesson 3: Weather Forecast
Show what you know!
1. What instruments are used to measure
weather variables?
2. How are computer models used to predict
the weather?
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