Air Masses and Fronts
Movements of Air Masses and Fronts are vital to our understanding and prediction of Weather Systems.
Terms to Know:
 What is an Air mass- a huge body of air that has similar temperature,
humidity, and pressure.
There are 4 kinds of air masses:
Tropical- or warm air masses form in the tropics and have low
air pressure
Polar- or cold air masses from North of 50o N latitude and
South of 50o S latitude.
Maritime- air masses that form over oceans
Continental- air masses form over land in the middle of
continents and are dry.
What is a Front- the area where the masses meet and do not
mix.
Occluded- the warm air masses are cut off.
Cyclone- a swirling center of low air pressure.
Anticyclone- area of high-pressure centers of dry air.
What is an air mass?
An air mass is a large body of air with similar temperature and/or humidity
Occupies thousands of square miles of the Earth’s surface, and can be several miles high
Air Masses are thus identified by letter codes, indicating their moisture and temperature
characteristics, and their sources regions
What are Source Regions?
They are stable source regions located in the subtropics or near the poles of the Earth.
The surface of the source region is Identified by lowercase letters, c, and m]
with associated Moisture characteristics
 Continental (c)  Forms over land  dry
 Maritime (m)
 Forms over ocean  moist
itudinal extent of source region [Cap letters, E, T, P and A]
with associated Temperature characteristics
 Equatorial (E)  Very low latitudes  warm
What are the types of air masses in north America?
Arctic
Continental
polar
Maritime
polar
• mP- maritime polar air mass
Maritim
tropica
• cP – continental polar air mass
• mT – maritime tropical air mass
• cT – continental polar air mass
Continental
tropical
Polar Maritime
(PM)
Source: Greenland
and Canada
Arctic Maritime
(AM)
Source: Within
the Arctic Circle
Polar Continental
(PC)
Source: Eastern
Europe and Siberia
Tropical Maritime
(TM)
Source: Caribbean,
moves with the
Westerlies
Tropical Continental
(TC)
Source: North Africa
and the Sahara
Note – these air
masses can affect the
whole of the UK, not
necessarily just where
the arrow points!
North America is affected by 5 types of air masses –
Maritime Tropical
• Warm humid air masses from
oceans near the tropics.
• They form over the Gulf of
Mexico and the Atlantic
Ocean.
• In the summer time maritime
tropical usually bring hot
humid weather.
• In winter, a humid air mass
can bring heavy rain or snow.
• Warm air forms over tropical regions near the equator.
T- Tropical
• Cold air forms over polar regions.
P- Polar
• Wet air masses form over water
m- maritime
• Dry air masses from over land.
c- continental
8
9
Temperature and moisture characteristics of the air masses –
Continental Polar
 Form over central and
northern Canada and Alaska.
 Bring cool and cold air.
 In winter they bring clear,
cool, and dry air to most of
northern America.
 In the summer, storms may
occur when continental air
masses move south and meet
maritime tropical that move
north.
12
• Moisture content is noted by the first letter.
m – maritime – wet
c – continental – dry
• Temperature is noted by the second letter.
P – polar – cool
T – tropical - warm
13
Global Distribution of Air Masses
Maritime Polar
 Cool humid air masses form
over the icy cold North Pacific
and North Atlantic oceans.
 The air masses affect the west
coast more than the east coast.
 In the summer they often
bring rain, fog, and cool
temperatures to the west coast.
Continental Tropical
 Hot dry air masses form only
in the summer over dry areas
of southwestern and northern
Mexico.
 Cover a smaller area than other
air masses.
 Bring hot, dry weather to the
south.
Maritime Polar (mP), cool and moist; brings mild weather to coastal locations.
Maritime Tropical (mT), warm and moist; responsible for much of the precipitation
east of the Rocky Mountains.
Maritime Equatorial (mE), form near the equator; very warm and humid; convection
and convergence of these in the ITCZ responsible for heavy rainfalls in the
equatorial rainforests.
 The North American region is affected by the first five
(cA, cP, cT, mP, mT -- See Map)
types of air mass
 Note: often a lower case “k” or “w” may be added to
air mass names to
indicate if they are colder (k) or warmer (w) than the surface below;
e.g., mTk or mTw – may suggest stability or instability in the air mass.
How do air masses move?
 The prevailing westerlies are
the major wind belts in the
United States.
 Prevailing westerlies push air
masses from west to east.
Interacting Air Mases and
Weather- Reference
TERMS TO KNOWINFORMATIONAL TEXT5E Lesson- Engage,
Explore, Explain,
Elaborate, Evaluate and
Enrichcement.
HYPERLINKS
Videos
Articles
SUMMARIZING SKILLSDefine
READING COMPREHENSION
Formative assessment.
Match, label, define
Digital Google Slides
MS-ESS2-5. Collect data to provide evidence for how the motions and
complex interactions of air masses results in changes in weather conditions.
Warm up- Q2- WEEK 2 - Read this informational text and answer the next questions – silently- independent work).
Why is the Earth Heated Unevenly? Think about where you live.
What is the climate like? If you live near the equator most likely it's
warm and wet. But, if you live farther north the temperature and
precipitation depends on the season. It can be hot and humid, or
freezing cold! Other areas of the globe reliably get very little rain,
creating vast expanses of desert. Why don't tropical areas get
cold? Why do deserts get so little rain? The answer is due to
uneven heating of the Earth by the Sun. The Earth is a sphere, and
so is the Sun. When the Earth orbits the Sun, the center of the
Earth gets more direct sunlight than the poles. This is intensified
by the Earth's tilt. Since the center of the Earth gets more sunlight,
it is consistently hotter than other parts of the Earth. When air is
hot, it rises. It creates low-pressure areas that draw air from other
areas in, creating wind. This heating and cooling of the air on Earth
causes
all theisclimate
and weather patterns we know.
Q1. What
causing
the weather patterns
on Earth? Explain:
___________________
Warm up- Q2- WEEK 2 - Read this informational text and answer the next questions – silently- independent work).
How the Sun Heats the Earth’s Surface: Water heats up and cools
down more slowly than land surfaces. Water particles do not move
too quickly and are slow to heat up and cool down. It takes a lot of
energy to raise the temperature of a volume of water. The energy
required to change that temperature is called heat capacity, and
water has one of the highest heat capacities in all substances.
This is one reason we see differences in temperature between the
land and water. During the day, the Sun warms the surface of the
ocean water, but the ocean currents and waves move colder water
from deeper depths to mix with the surface water. During the day,
land heats up faster than the ocean, and at night, it cools faster.
Land surfaces do not have the heat capacity or mixing like ocean
water. Unequal heating and cooling also occurs between seasons.
The unequal heating and cooling creates pressure differences,
which ultimately cause wind.
Q1. Does land and water
heat differently? Explain
Why: ___________
Air Masses
North American air masses: An air mass takes on the conditions of the area where it forms. For
example, a continental polar air mass has cold dry air. A maritime polar air mass has cold moist air.
Which air masses have warm moist air? Where do they form?
Movement of Air Masses
When a new air mass moves over a region it brings its
characteristics to the region. This may change the
area's temperatureWhen a new air mass moves over a
region it brings its characteristics to the region. This
may change the area's temperature and
humidityWhen a new air mass moves over a region it
brings its characteristics to the region. This may
Summary
•An air mass has roughly the same
temperatureAn
air mass
has roughly the
same
temperature
and
change
the area's
temperature
and
humidity.
Moving
humidity.
air masses cause the weather to change when they
•Air masses form over regions where the air is stable for a long enough time. The air takes on the
contact different conditions.
characteristics of the region.
•Air masses move when they are pushed by high level winds.
Why do air masses move? Winds and jet streams
push them along. Cold air masses tend to move
toward the equator. Warm air masses tend to move
toward the poles. The Coriolis effect causes them to
move on a diagonal. Many air masses move toward
the northeast over the U.S. This is the same direction
that global winds blow.
Formation of Air Masses
An air mass is a batch of air that has a uniform
temperature and humidity. An air mass acquires
these characteristics from the land or water
that it is above. Air masses are very large and
form in high-pressure zones such as polar and
tropical regions. Temperate regions are too
unstable for air masses to form, creating unique
weather in these areas. Weather changes occur
with changes in air masses
Air Mass Movement
Air masses move when they are
pushed by high-powered winds. Once
they move, they gain new
characteristics based on the area
they are positioned over. Storms are
caused when an air mass moves over
a region with different characteristics.
For example, warm air masses
moving over cold landmasses cause
storms. Cold air masses tend to flow
towards the equator and warm air
masses tend to flow toward the poles.
This helps balance the temperature of
the earth.
Differences in air pressure at different
locations on earth create wind
patterns. The equator receives more
solar energy than the poles, heating
the air, causing it to rise. Cold, polar
air sinks. As air moves from high to
low pressure, a general, worldwide
movement of surface air from the
poles toward the equator occurs.
Air Masses that affect U.S. weather:
Air masses are distinguished by one of four source
characteristics:
1. Polar (sometimes called Arctic)
2. Tropical
3. Continental (land regions)
4. Maritime (water regions)
• As air masses move, they become modified such that they
show characteristics of two source regions
• cP = continental Polar
• mT = maritime Tropical
The Jet Stream is like a river of wind high above
in the atmosphere. These slim strips of strong
winds have a HUGE influence on climate, as they
can push air masses around and affect weather
patterns.
Jet Stream is a band of wind high above the
atmosphere
➢ Jet Stream runs WEST to East
➢ Barrier between Hot and Cold Air.
➢ Greater the temperature difference the faster
it moves.
➢ Pushes Air Masses around.
➢ JET STREAM= FAST WIND that MOVES
WEATHER AIR MASSES.
The Coriolis Effect is the curving of the wind
caused by the Earth’s rotation. The Coriolis
Effect plays an important part in the movement
of different weather patterns all around the
world. Especially when it comes to ocean
current like the Gulf Stream .
Curving of the wind caused by Earth’s
Rotation.
•
A front is a boundary between air masses.
•
Four types of fronts and map symbols
1.
2.
3.
4.
Cold front
Warm front
Occluded front
Stationary front
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COLD FRONT
• Cold air mass meets a warm air mass and
pushes the warm air mass out of its way.
• Bring thunderstorms, rain or snow.
• Most tornadoes develop from
• thunderstorms on the edge of a cold front.
• Cold front followed by cooler drier air.
30
WARM FRONT
• Warm air mass meets a cold air mass and pushes the cold air
mass out of the way.
• Brings drizzly precipitation.
• Followed by clear warm weather.
31
STATIONARY FRONT
• Cold air meets warm air.
• Not enough force to move either front.
• Many days of cloudy, wet weather.
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OCCLUDED FRONT
• Warm air caught between two cold air masses.
• Brings cool temperatures with large amounts of rain or snow
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Cold Front, Warm Front and
Occluded Front Animation
• http://www.3villagecsd.k12.ny.us/Murphy/medin
a/weather.html
• http://www.classzone.com/books/earth_science
/terc/content/visualizations/es2002/es2002page
01.cfm?chapter_no=visualization
• Click on the above links.
34
35
Fronts
• When an air mass moves into an area and interacts with other
masses, it causes the weather to change.
• The boundary where air masses meet becomes a front
Fronts
 When air masses meet is a
front, the collision often
causes storms and weather
changes.
 A front may be 15 to 200
kilometers wide and extend as
much as 10 kilometers up to
the troposphere.
 The kind of front that
develops depends on the
characteristics of the air
masses and how they move.
• Fronts are boundaries that
air masses
Whatseparate
is a Front?
• Where air masses meet
and do not mix.
4 Types of Fronts:
Cold Front
Warm Front
Stationary Front
Occluded Front
 Note: The direction the teeth or the bumps face
is the direction the front is moving
There are four types of fronts.
 Cold Fronts.
 Warm Fronts.
 Stationary Fronts.
 Occluded Fronts.
Cold Front
When a fast moving cold air mass runs into a
slow moving warm air mass and the thicker
cold air slides under the lighter warmer air.
Cold Fronts
• Cold air is dense and tends to sink.
• Warm air is less dense and tends to
rise.
• When a moving cold air mass runs
into a slowly moving warm air mass,
the denser cold air slides under the
warmer air.
• Warm air can hold more water vapor
than cool air.
• If there is a lot of water vapor in the
warm air heavy rain or snow may fall.
• Cold fronts move quickly so they can
cause weather changes.
• After a cold front passes, cool, dry
air moves in.
COLD FRONT
 Cold air displaces warm air upward
 Much steeper than warm fronts
 Advances faster than a warm front
 Violent weather – Cumulonimbus
clouds, thunderstorms,
tornadoes,
hail, short, sharp
Cold Front
Fast moving cold
dense air pushes
slow moving
warm air up
Warm air cools
and precipitates
Since cold air masses move fast they can cause abrupt
weather changes (thunder storms)
After a cold front passes, colder, drier air moves in
bringing clear skies
Warm Front
When a moving warm air mass collides with a
slowly moving cold air mass and the warm air
moves over the cold air.
Warm Fronts
 A moving warm air mass collides
with a slowly moving cold air mass.
 If the warm air is humid showers
and light rain might. fall along the
front where the warm and cold air
meet.
 If the warm air is dry scattered
clouds may form.
 After a warm front passes through
an area the weather is likely to be
warm and humid.
 Winter warm fronts bring snow.
WARM FRONT
 Warm air replaces cold
 Gentle slope (1:200)
 Covers a wide area with its weather
 Stratus clouds get lower as front
approaches – Drizzle or steady rain
Warm Front
Fast moving
warm air
overtakes
slow moving
cold air
Less dense warm air moves over dense cold air
Can produce rain or snow
Area likely to become warm and humid
Warm Front
Stationary Front
When a cold air mass and warm air mass
meet, but neither air mass has enough force
to move the other air mass.
Stationary Fronts
Cold air and warm air
meet but neither can
move the other.
Produces rain, snow
or fog
Can last for several
days
Standoff between two air masses
Stationary Fronts
Standoff between two air masses
Stationary Fronts
 Sometimes cold and warm air
masses meet but neither one
has enough force to move.
 Where the warm and cold air
meet, water vapor in the
warm air turns into rain,
snow, fog, or clouds.
STATIONARY FRONT
 Cold and warm air masses
next to each other
 Neither air mass advances
 Areas under them experience clouds,
drizzle and rain (even possible
thunderstorms) for several days
Occluded Front
When a warm air mass is caught between two
cooler air masses and the thicker cold air
masses move underneath the thinner warm
air mass and push it upward.
Occluded Front
A warm air mass is caught between two cold air masses
The denser air mass pushes the warm air mass up
The two cold air masses may mix underneath the warm one
The warm air mass is cut off (occluded) from the ground
The warm air cools, condenses and may precipitate
Occluded Fronts
 A warm air mass is caught
between two cooler air masses.
 As warm air cools and its
water vapor condenses, the
weather may turn cloudy, rainy,
or snowy.
OCCLUDED FRONT
 Faster-moving cold front
overtakes a warm front –
usually occurs in the latter stages
of a mid-lattitude cyclone
 Lifts all the warm air off the ground
 Clouds and rain possible
Which types of Fronts and Weather Systems
can you find on this map? Weather Reports
Daily Weather Map: Map Interpretation and Weather Forecasting
Daily Weather Map from February 4, 2019
1. What are the highest and lowest values for isobars on this map? Highest ________ Lowest ________ mb.
2. Where is the pressure gradient the steepest? __________________________________________________
3. What different types of front do you see on this map? ___________________________________________
4. What kind of air mass is dominating much of Canada and north-central U.S.? _________________________
5. Which part of the U.S. is currently enjoying clear skies and rain-free weather? ________________________
6. How would you describe the weather condition in Northern California? _____________________________
7. How and why would you expect the weather to change in Los Angeles area in the next few hours and days?
8. Why do you think Texas may experience rain in the next hours and days? ____________________________
Cyclones and Anticyclones
• As warm air at the center of a cyclone rises , the air
pressure decreases.
• Winds in s cyclone spin counterclockwise in the
Northern Hemisphere.
• As air rises in a cyclone the air cools forming clouds
and precipitation.
• Winds spiral outward from the center of an
anticyclone, moving towards areas of low pressure.
• Winds in an anticyclone spin clockwise in the
Northern Hemisphere.
Cyclones
• Hurricanes are very large
cyclones that can cause
widespread damage.
Anticyclones
• Air flows clockwise
around a high-pressure
system in the northern
hemisphere.
• Air tends to sink near
high-pressure centers,
which inhibits
precipitation and cloud
formation.
Cyclones
• Swirling low pressure system
• Air pressure decreases as warm air rises
• Cooler air blows inward toward the low pressure area
• Coriolis effect causes the wind to spin counterclockwise in northern
hemisphere
• Associated with clouds, wind, and precipitation
• Area with lower pressure than surrounding area.
• Winds spiral toward the center.
• Rising air causes stormy weather.
• Hurricanes that from over the Indian Ocean are called
cyclones.
70
Anticyclones
• High pressure systems
• Air swirls outward in clockwise direction in northern hemisphere
• Cool air moves downward and heats up lowering relative humidity
• Associated with dry, clear weather
• Rotation of air around high pressure center.
• Dry, clear weather
72
Cyclones & Anticyclones
• Fronts become distorted because of things like mountains or jet streams
(bending)
• Bending can cause swirls which can create low pressure centers
Section 1 Review
1.) What two main characteristics are used to classify air
masses?
• Temperature
• Humidity
Section 1 Review
2.) What's a front? Name and describe the four fronts.
 Front- the area where the masses meet but do not mix.
 Cold Fronts- when a rapidly moving cold air mass runs into a
slowly moving air mass, the denser cold air slides under the
lighter warm air.
 Warm Fronts- a moving warm air mass collides with a slowly
moving cold air mass.
 Stationary Fronts- sometimes cold and warm air masses meet
but neither one has enough force to move.
 Occluded Fronts- a warm air mass is caught between two
cooler air masses.
Section 1 Review
3.) What
is a cyclone? What kind of weather does it
bring?
Cyclone- a swirling center of low air pressure.
A cyclone usually brings precipitation and usually
forms clouds.
Section 1 Review
4.) Why do maritime polar air masses have more affect on the west coast
than the east coast?
 Maritime polar air masses has more affect on the west coast than the
east coast because,
of the cool humid air.
Quiz: Take this on the paper provided.
1. Describe a maritime polar (mP) air mass, in terms of moisture and temperature.
2. What is the name of an air mass that forms over water?
3. What is the name of an air mass that forms over land?
4. What is the name of an air mass that forms in a cold region?
5. What is the name of an air mass that forms in a warm region?
6. Describe a continental tropical (cT) air mass, Moisture and temperature.
7. The boundary between two air masses is called a ______________________.
8. A cold air mass meets and pushes a warm air mass out of the way.
What type of front am I?
9. A warm air mass is trapped between to cold air masses.
What type of front am I?
10. A warm air mass meets and pushes a cold air mass out of the way.
What type of front am I?
11. I am a front that brings drizzly rain and am followed by warm clear weather. Name
me
12. A cold air mass meets a warm air but neither is very strong. They are separated
and many days of wet , cloudy weather occur.
78
Connect your learning –Name the air masses, their codes and sources
below
Name:
Code:
Source
Name:
Code:
Source
Name:
Code:
Source
Name:
Code:
Source
Name:
Code:
Source:
Note – these air
masses can affect the
whole of the UK, not
necessarily just
where the arrow
points!
Air Masses
Use the
information
sheet on Air
Masses to
complete the
table
describing
each air mass
Code
Source
regions
Surface
travelled
over?
Circle one
Air
temperat
ure?
Circle one
Polar
Maritime
Ocean or Land
Warm or Cold
Polar
Continental
Ocean or Land
Warm or Cold
Tropical
Maritime
Ocean or Land
Warm or Cold
Tropical
Continental
Ocean or Land
Warm or Cold
Arctic
Maritime
Ocean or Land
Warm or Cold
Directio
n of
Travel
Temper Rainfall
ature
?
increas
ing or
decrea
sing?
Which air mass is most likely to…
1. Have children reaching for their sledges?
2. Increase the sales of ice cream?
3. Cause water shortages?
4. Creating problems for flooding on the nations rivers?
5. Affect the West of the country the most?
6. Bring snow to Northern Scotland?
7. Bring snow to Eastern England?
8. Bring out the brollies?
9. Travel over the North Atlantic?
10.Make people turn up their heating?
11.Bring Saharan dust to the UK?
Air Masses - Review
https://quizlet.com/_8r
17yr?x=1qqt&i=ay3h
Air masses and climate change
1850
1900
How might Polar
maritime air, our
dominant air mass,
change as the
Atlantic warms?
1950
2000
2018
Thunk
Question
Where in the UK is
there the most
weather?
Air Masses
Objectives
Outcomes
1. To be able to describe the 5
major air masses that affect the
UK.
2. To be able to explain what
weather the major air masses
bring to the UK.
3. To be able to draw compass rose
diagrams and infer which air
masses affect the UK most.
4. To consider how air masses
affect day to day life in the UK.
1. Video notes and a completed
table on the 5 air masses
affecting the UK.
2. A completed compass rose
diagram.
3. Explained decisions on air mass
“most likely to” statements.
Air masses – diagrams from text
1. Task - Try to draw the words as I speak them – no words allowed, only
pictures/sketches
2. Read your diagrams back to a partner
3. Now use the definition below to write 2 sentences summarising what an air mass
is.
An air mass is a volume of air with very similar temperature and humidity
characteristics.
Air masses cover many hundreds or thousands of miles.
They adapt to the characteristics of the surface below them.
They are classified by where they come from and which path the wind takes.
Fronts mark the boundary between two distinct air masses.
What are air
masses?
https://www.youtube.com/watch?v=kvk-hBFnBTI
Watch the video and take some notes as it plays
What are air
masses?
https://youtu.be/kvk-hBFnBTI
DID YOU KNOW? Winds are
named by the direction that
they are blowing from!
RECAP Exercise- try to answer the
questions now. If you have any gaps
complete them as the video plays a
second time.
1. What characteristics do air masses
have that sit over hot deserts like
in North Africa?
2. What is their special name?
3. What does the term “continental”
mean?
4. What is a polar continental air
mass?
5. What weather does a Polar
continental air mass bring to the
UK?
6. Where do Polar Maritime air
masses originate?
7. What does the warm sea water do
to a Polar Maritime air mass as it
travels over it?
8. What weather does Polar
Maritime bring to the UK?
9. When does the UK get its most
severe weather?
What are air
masses?
https://youtu.be/kvk-hBFnBTI
In summary – copy these definitions into your books;
1. Polar or Arctic airmasses come from colder regions
2. Tropical air masses come from warmer regions
3. Continental means the air mass is generally dry or lacking in humidity as it has
passed over the LAND
4. Maritime means the air mass is generally humid as it has passed over the OCEAN
Polar Maritime
(PM)
Source: Greenland
and Canada
Arctic Maritime (AM)
Source: Within the
Arctic Circle
Polar Continental
(PC)
Source: Eastern
Europe and Siberia
Tropical Maritime
(TM)
Source: Caribbean,
moves with the
Westerlies
Tropical Continental
(TC)
Source: North Africa
and the Sahara
Note – these air masses
can affect the whole of
the UK, not necessarily
where the arrow points!
Code
Air Masses
Use the
information sheet
on Air Masses to
complete the
table describing
each air mass
Extension –
What would the
weather be like if a
Tropical air mass
arrived in the UK in
WINTER?
What would the
weather be like if a
Polar maritime air
mass arrived in
SUMMER?
Polar
Maritime
Polar
Continen
tal
Tropical
Maritime
Tropical
Continen
tal
Arctic
Maritime
Source
regions
Surface
travelled
over?
Air
temperature
Direction of
Travel
Humidity
increasing
or not?
Temperature
increasing or
decreasing?
Convection?
Rain
fall?
Polar Maritime
Code
Source
regions
Surface
travelled
over?
Air
temperature
Direction of Travel
Humidity
increasing or not?
Temperature
increasing or
decreasing?
Convection?
Rainf
all?
Pm
Eastern
Canada
and
Greenland
Ocean
Cold
towards the
south-east
Yes, it picks up
a lot of
moisture over
the Atlantic
Increasing (it
warms as it
moves south)
Yes, warm
air rises
Yes,
espe
cially
on
west
coast
Very dry but
picks up
moisture as it
passes over the
North Sea
Yes, it picks up
a lot of
moisture over
the Atlantic
Increasing
Yes, warm
air rises
Som
e on
east
coast
Being cooled
from below
as it moves
North
No, no
convection
in cooling air
Drizz
le
decreasing
No – only
some
isolated
thunderstor
ms
Only
in
some
isolat
ed
thun
derst
orms
Yes,
partic
ularly
in the
north
Polar Continental Pc
Siberia and Mostly
Scandinavi land
a
Very cold
towards the
west or southwest
Tropical
Maritime
Tm
Atlantic, at
the edge
of the
Tropics
Ocean
Warm
towards the
north-east
Tropical
Continental
Tc
North
Africa
Land
the
warmest
air the UK
gets
towards the
north
Not, it is the
driest air the
UK gets
Arctic Maritime
Am
Arctic
regions
Ocean
Extremely
cold
Towards the
south
Yes, moisture
Increasing
from the Ocean
Yes
Polar Continental
(PC)
Source: Eastern
Europe and Siberia
Think, Pair, Share:
What do you think Polar Continental air is like
a) In Winter
b) In Summer?
10 11 12 13 14 15
Title:
NNW
1. Plot the compass rose diagram
using the data in the table
2. What does the diagram reveal
to you about the most common
wind direction?
3. Which Air masses could this be?
NNE
NE
%
2
North North East (NNE)
3
4
North East (NE)
6
East North East (ENE)
4
East
3
East South East (ESE)
3
South East (SE)
2
South South East (SSE)
2
South
4
South South West (SSW)
7
South West (SW)
14
West South West (WSW)
13
West
West North West
(WNW)
11
North West (NW)
8
North North West
3
7 8
Compass direction
North
2 3
9
NW
N
6
WNW
1
5
ENE
W
15 14 13 12 11 10 9
8
7
6
5
4
3 2
1
E
1
2 3
4
5
6
7 8
9
10 11 12 13 14 15
1
2 3
4
5
ESE
6
WSW
7 8
9
10 11 12 13 14 15
SW
SSW
S
SE
SSE
Remember that winds are named by the direction they are blowing FROM
15
10 11 12 13 14 15
Title: A wind compass rose for Cardington, UK
NNW
NNE
NE
%
2
North North East (NNE)
3
4
North East (NE)
6
East North East (ENE)
4
East
3
East South East (ESE)
3
South East (SE)
2
South South East (SSE)
2
South
4
South South West (SSW)
7
South West (SW)
14
West South West (WSW)
13
West
West North West
(WNW)
11
North West (NW)
8
North North West
3
7 8
Compass direction
North
2 3
9
NW
1. Plot the compass rose diagram
using the data in the table
2. What does the diagram reveal
to you about the most common
wind direction?
3. Which Air masses could this be?
N
6
WNW
1
5
ENE
W
15 14 13 12 11 10 9
8
7
6
5
4
3 2
1
E
1
2 3
4
5
6
7 8
9
10 11 12 13 14 15
1
2 3
4
5
ESE
6
WSW
7 8
9
SSW
10 11 12 13 14 15
SW
S
SE
SSE
15
Which air mass is most likely to…
1. Have children reaching for their sledges?
2. Increase the sales of ice cream?
3. Cause water shortages?
4. Creating problems for flooding on the nations rivers?
5. Affect the West of the country the most?
6. Bring snow to Northern Scotland?
7. Bring snow to Eastern England?
8. Bring out the brollies?
9. Travel over the North Atlantic?
10.Make people turn up their heating?
11.Bring Saharan dust to the UK?
Air Masses - Review
Quizlet time
Key terms –
https://quizlet.com/500963386/rmetsair-masses-flash-cards/
Images task https://quizlet.com/_8tb293?x=1qqt&i=
ay3h
Air masses and climate change
1850
1900
How might Polar
maritime air, our
dominant air mass,
change as the
Atlantic warms?
1950
2000
2018
Extension – Can you work out what
the air masses affecting the UK have
to do with global atmospheric
circulation?
Rising
Sinking
COLD
Low Pressure
Westerlies
Sinking
High Pressure
Easterly
Trade winds
Rising
Low Pressure
HOT
Easterly
Trade winds
High Pressure
Sinking
Westerlies
Rising
Low Pressure
COLD
Sinking
Thunk
Question
Thunk question
“A Thunk
question is
a…simple-looking
question about
everyday things
that stops you in
your tracks and
helps you start to
look at the world
in a whole new
light.”
https://www.indep
endentthinking.co.
uk/thunks/
n.b. Thunk in this
sense is not an
official word in
the Cambridge
English
Dictionary!
Where in the UK is
there the most
weather?
A word on simplification….
• Air masses often meet
over the UK, this gives
rise to depressions (the
UK’s storm systems) and
fronts
• Size of air masses and
arrows are representative
ONLY. Air masses vary in
size and can affect much
of the UK at the same
time
• Returning Polar Maritime
is another air mass that
exists – it dips south
through the Atlantic and
warms as it then
“returns” North
Eastwards to the UK
Connect your learning Global Atmospheric
Circulation Practice
1. Fold your A3 sheet into four.
2. For each round, draw and label what you see in the
presentation, in one box.
3. On the next round, swap your sheet with a partner,
do the same as in point 2, but in a new box. No
peeking at the previous box(es) – this is a memory
exercise!
4. It gets faster and harder with each round – work
quickly!!!
Round 1
Round 2
Round 3
Round 4
Sinking
Rising
COLD
Low Pressure
Westerlies
Sinking
High Pressure
Easterly
Trade winds
Rising
Low Pressure
HOT
Easterly
Trade winds
High Pressure
Sinking
Westerlies
Rising
Low Pressure
COLD
Sinking
Sinking
Rising
COLD
Low Pressure
Westerlies
Sinking
High Pressure
Easterly
Trade winds
Rising
Low Pressure
HOT
Easterly
Trade winds
High Pressure
Sinking
Westerlies
Rising
Low Pressure
COLD
Sinking
Sinking
Rising
COLD
Low Pressure
Westerlies
Sinking
High Pressure
Easterly
Trade winds
Rising
Low Pressure
HOT
Easterly
Trade winds
High Pressure
Sinking
Westerlies
Rising
Low Pressure
COLD
Sinking
Sinking
Rising
COLD
Low Pressure
Westerlies
Sinking
High Pressure
Easterly
Trade winds
Rising
Low Pressure
HOT
Easterly
Trade winds
High Pressure
Sinking
Westerlies
Rising
Low Pressure
COLD
Sinking
Turn over your sheet and see how much you can draw from
memory!
Alternative Connect your Learning:
Try this Quizlet set;
https://quizlet.com/_8y57ol?x=1jqt&i=38anvz
Air Masses
Air Masses
Objectives
Outcomes
1. To be able to describe the 5
major air masses that affect the
UK
2. To be able to explain what
weather the major air masses
bring to the UK
3. To consider how air masses
affect day to day life in the UK.
1. Video notes and a completed
table on the 5 air masses
affecting the UK
2. Explained decisions on air mass
“most likely to” statements.
Air masses – diagrams from text
1. Task - Try to draw the words as I speak them – no words allowed,
only pictures/sketches
2. Read your diagrams back to a partner
3. Now use the definition below to write 2 sentences summarising what an air mass
is.
An air mass is a volume of air with very similar temperature and water humidity.
Air masses cover many hundreds or thousands of miles.
They adapt to the characteristics of the surface below them.
They are classified by where they come from and which path the wind takes.
What are air
masses?
https://www.youtube.com/watch?v=kvk-hBFnBTI
Watch the video and take some notes as it plays
What are air
masses?
RECAP Exercise- try to answer the
questions now. If you have any
gaps complete them as the video
plays a second time.
1. What characteristics do air
masses have that sit over hot
deserts like in North Africa?
2. What is their special name?
3. What does the term
“continental” mean?
4. What is a polar continental
air mass?
5. What weather does a Polar
continental air mass bring to
the UK?
https://www.youtube.com/watch?v=kvk-hBFnBTI
6. Where do Polar Maritime air
masses originate?
7. What does the warm sea
DID YOU KNOW? Winds are
water do to a Polar Maritime
named by the direction that they
air mass as it travels over it?
are blowing from!
8. What weather does Polar
Maritime bring to the UK?
9. When does the UK get its
most severe weather?
What are air
masses?
https://www.youtube.com/watch?v=kvk-hBFnBTI
In summary – copy these definitions into your books:
1. Polar or Arctic airmasses come from colder regions
2. Tropical air masses come from warmer regions
3. Continental means the air mass is generally dry or lacking in humidity as it has
passed over the LAND
4. Maritime means the air mass is generally humid as it has passed over the OCEAN
Polar Maritime
(PM)
Source: Greenland
and Canada
Arctic Maritime (AM)
Source: Within the
Arctic Circle
Polar Continental
(PC)
Source: Eastern
Europe and Siberia
Tropical Maritime
(TM)
Source: Caribbean,
moves with the
Westerlies
Tropical Continental
(TC)
Source: North Africa
and the Sahara
Note – these air masses
can affect the whole of
the UK, not necessarily
where the arrow points!
Polar Continental
(PC)
Source: Eastern
Europe and Siberia
Think, Pair, Share:
What do you think Polar Continental air is like
a) In Winter
b) In Summer?
https://www.metlink.org/resource/7-airmasses/
Types of Air Masses
Warm Up Question
What do you think air masses are and how do they relate to
weather?
Jet Stream
The jet stream is a current of fast moving air found in the upper levels of the
atmosphere. Moves air from the west coast to the east coast. They transport
our weather throughout the US. Strong winds ranging from 120 mph
to 250 mph.
Copy down first two sentences.
How do they classify air masses?
According to…temperature and humidity.
Temperature affects Air Pressure: colder temps have higher pressure and
warmer temps have lower air pressure.
When air masses move into different areas it causes weather to
change.
Jet Stream and Prevailing Westerlies move air masses. Jet Stream
blows from W to E.
Draw a quick
picture of this
L
A
B
E
L
T
H
I
S
O
N
Y
O
U
R
M
A
P
Type of Air Mass
Continental
Tropical
Maritime
Tropical
Continental
Polar
Maritime
Polar
Where does it come
from
Type of weather
associated with the air
mass
What area does it
affect?
Reading Activity:
Read through the information on the handout on
the next three slides and fill out your chart.
Watch this video if you have time:
https://www.youtube.com/watch?v=rQbqujJ
GJRg