Transcript Air Masses, Fronts, and Severe Weather

Air Masses, Fronts, and
Severe Weather
Earth Science
Grade 8
Air Masses
 An
air mass is a body of air
that has the same properties
as the area over which it
developed.
Air Masses
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There are four categories that determine
an air mass’s characteristics:
developed over land: continental = c
developed over water: maritime = m
developed over cold area: polar = P
developed over warm area: tropical = T
Air Masses
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Air masses that could develop:
(Combine the two possibilities)
1. cT
2. mT
3. cP
4. mP
Fronts
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Fronts are where two air masses meet.
Their names are determined by the
moving air mass.
Precipitation occurs along all fronts
Four Types of Fronts
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COLD FRONT
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When cold air moves into an area of warmer air
Weather caused: Thunderstorms and heavy rain
It’s symbol on a weather map looks like this:
Four Types of Fronts
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WARM FRONT
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When warm air moves into an area of colder air
Weather caused: long, steady rains
It’s symbol on a weather map looks like this:
Four Types of Fronts
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OCCLUDED FRONT
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When colder air moves into an warmer area
of air at an angle. The masses start to spin!
Weather caused: severe weather like tornados
It’s symbol on a weather map looks like this:
Four Types of Fronts
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STATIONARY FRONT
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When two air masses do not move!!!
Weather caused: same weather for days (all nice or
all bad)
It’s symbol on a weather map looks like this:
Severe Weather
Thunderstorms
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Thunderstorms result from the rapid
upward movement of moist air.
As this air moves upward it cools,
condenses, and forms cumulonimbus
clouds
Cumulonimbus
Clouds
Cumulonimbus Cloud with
Lightning
Lightning
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Lightning is a large release of energy during a
thunderstorm
Thunder is the rapid heating of the air
surrounding the lightning bolt…fast enough to
break the sound barrier!
http://www.youtube.com/watch?v=h7c6z_3dLE4&feature=related
Hail
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In thunderstorms the updrafts can be so
severe that the rain coming down can be
thrown back up into the cloud.
This causes the rain to freeze in layers
creating hail.
Hail formation
Tornadoes
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When thunderstorms reach extremely low
pressures, they can create tornadoes.
Tornadoes are violent whirling winds that
move in small areas over land.
Even though the are relatively small
storms, and last for only a few minutes,
they are one of the MOST DESTRUCTIVE
storm on land.
Tornadoes
Water Spouts
Tornado Sisters
Fujita Scale
Measures the destruction of the Tornadoes
Most Famous Tornado
http://www.youtube.com/watch?v=MhPu5AHDMHM
Hurricanes
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The largest and most powerful storm on
the planet is the Hurricane.
It is a large, swirling, low pressure system
that forms over tropical oceans along the
equator.
Hurricane Formation
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A storm develops over the ocean is first called a
tropical depression. Wind speed up to 38 mph
Once the winds reach 39 mph the depression
becomes a tropical storm and gets a name.
Once the winds reach 74 mph the storm
becomes a hurricane. A hurricane will continue
to grow as long as it is over warm, tropical
waters.
Hurricane Names
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Hurricanes are named alphabetically
switch from boy to girl (or girl to boy).
2010
2011
2012
2013
2014
2015
Alex
Bonnie
Colin
Danielle
Earl
Fiona
Gaston
Hermine
Igor
Julia
Karl
Lisa
Matthew
Nicole
Otto
Paula
Richard
Shary
Tomas
Virginie
Walter
Arlene
Bret
Cindy
Don
Emily
Franklin
Gert
Harvey
Irene
Jose
Katia
Lee
Maria
Nate
Ophelia
Philippe
Rina
Sean
Tammy
Vince
Whitney
Alberto
Beryl
Chris
Debby
Ernesto
Florence
Gordon
Helene
Isaac
Joyce
Kirk
Leslie
Michael
Nadine
Oscar
Patty
Rafael
Sandy
Tony
Valerie
William
Andrea
Barry
Chantal
Dorian
Erin
Fernand
Gabrielle
Humberto
Ingrid
Jerry
Karen
Lorenzo
Melissa
Nestor
Olga
Pablo
Rebekah
Sebastien
Tanya
Van
Wendy
Arthur
Bertha
Cristobal
Dolly
Edouard
Fay
Gonzalo
Hanna
Isaias
Ana
Josephine
Kyle
Laura
Marco
Nana
Omar
Paulette
Rene
Sally
Teddy
Vicky
Wilfred
Hurricane Names 2010-2015
Bill
Claudette
Danny
Erika
Fred
Grace
Henri
Ida
Joaquin
Kate
Larry
Mindy
Nicholas
Odette
Peter
Rose
Sam
Teresa
Victor
Wanda
Eye and Eye Wall of the Hurricane
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The eye of the storm is the calm area in
the center of the storm.
The eye wall is the bank of clouds
immediately next to the eye…this is the
most severe part of the storm.