Download Air masses and extreme weather student booklet

1
Science 421 - North American Weather Systems
Text Section 14.2 North American Weather Systems. Read page 546 and refer to Figure 1.
a.
An air mass is a
of
has the same amount of
b.
which has the same temperature of air and
.
When air moves over large bodies of water, such as the oceans on the east and west coasts of North
America, it picks up water vapour and becomes moister. The name of moist air masses found along
coastlines begin with the word
(begins with m).
When air moves over land, such as in the centre of North America, it does not pick up more moisture.
The name of dry air masses over the centre of North America start with the word
(begins with c).
c.
There are 4 types of air masses over North America. Complete the table matching the description given
with the name of the type of air mass and the weather associated it with each description. The first one is
completed for you.
Description of Air
Mass
Cool, moist air
Name of Air Mass
Maritime Polar
Location where air masses
develop
i. North Pacific Ocean (West
coast of Canada)
ii. North Atlantic Ocean (East
Coast of Canada)
Weather Associated with Air
Mass
wet, stormy weather
Cold, dry air
Warm, moist air
Dry Warm Air
d.
Label the Diagram showing the location of the development of the North American Weather Masses
A.
B.
C.
D.
e.
Winds that affect major areas of the Earth are called prevailing winds. Air masses are moved about by
and
.
When air masses come in contact they create w
f.
g.
h.
i.
j.
k.
s
.
A weather system is a set of
,
,
, and
conditions that
for a
period of
.
Warm air is less dense and (rises away from/ sinks towards) the ground. This movement of air results in a
decrease in pressure.
Cold air is denser and (rises away from / sinks towards) the ground. This would result in an in (increase or
decrease) in pressure.
If an increase in pressure is described by meteorologists as a “high pressure” a decrease in pressure would
be called a
.
Describe the weather associated with a low pressure air mass
.
Describe the weather brought in by a high pressure weather system
.
2
Weather Fronts and Low Pressure Systems.
a.
Match the number of the weather front with the following descriptions and characteristics.
1. occluded front
2. warm front
3. cold front
4. stationary front
i.
a warm air mass is leading and pushes into a cold front.
ii.
a cold and warm air mass meet but neither is strong enough to overcome the other and they both
stop moving.
iii.
slow moving front
iv.
indicated on a weather map by red semicircles.
v.
results in the formation of cumulus clouds and often severe weather like thunderstorms.
vi.
often see high cirrus clouds with it
vii.
indicated by blue triangles
viii.
a cold front pushes in behind a warm front and overtakes it.
ix.
fast moving front.
b.
A low-pressure system that rotates counter-clockwise in the Northern Hemisphere and brings bad weather
is called a
.
c.
A high-pressure system that rotates clock-wise and bring bad weather is called a
d.
Identify the type of front.
i
ii
iii
.
iv
3
Science 421 Extreme Weather Events –Chapter 15
Fill in the blank with the following terms:
See the following pages in the text: 582, 584, 589, 594-596, 598-599, 605 for definitions
typhoons
blizzard
eye
weather watch
wind chill
drought
i.
tornado
thunderstorm
weather advisory
flood
hurricane
storm surge
weather warning
tropical storm
is a storm with lightening, thunder, heavy rain and sometimes hail.
ii.
means that severe weather, likely to cause local problems and
inconveniences , is predicted for your areas.
iii
hurricane and is pushed on shore.
a huge amount of water that is piled up by intense winds during a
iv
when reporting the temperature.
a calculation that takes the cooling effect of the wind into account
v
Australia.
is a tropical cyclone that develops in the Indian Ocean or around
vi
soak up anymore water.
is an excess of water from rain, rivers or oceans over land that cannot
vii
means that conditions are present for extreme weather to occur in
your area, so you should pay attention to further updates.
viii
may already be happening.
means that extreme weather is highly likely to arrive in your area or
ix
a severe component of a thunderstorm in which a rotating funnel of air
extends from the base of the clouds to the ground.
x
a severe snow storm with strong winds and low temperatures.
xi
a cyclone that develops in the Pacific Ocean or the China Sea.
xii
is a long period with much less rainfall than average.
xiii
the central core of a hurricane where the air is calm and the sky clear.
xiv
Caribbean Sea, the Gulf of Mexico.
a severe cyclone that occurs in the western Atlantic Ocean, the