Transcript Why weather- student P.P

Why Do We Have
Weather?
WHY DO WE HAVE THE WEATHER
?
• Just think about it!
• Why is there wind? Why does it blow
from one direction one day and another
the next?
• Why is it rainy one day and dry the
next?
• How come it’s cold in the winter?
• How can we have hail in the summer?
• What causes snow and freezing rain?
If we were to pick one term to help
explain why we have weather, what do you
think would be a good word?
You might pick heat or sun….but another
good choice would be
_______ currents
(hint: type of heat transfer: warm air rising,cools and falls back down)
Convection is the transfer of
______,
usually in _______ or liquids.
After the atmosphere is warmed by radiation and
conduction, heat is transferred throughout the
atmosphere by convection.
* warmed air has _____
space between molecules,
it’s _____ dense & rises
*Cooled air is more dense &
tends to sink
*In general, air near the
equator ______ & air
near the poles ______
The Coriolis effect-wind patterns
because of earth’s rotation
Take a look at this!
Notice the band of clouds
around the equator ?
This is the ITCZ zone
a.k.a ________________ _____________
__________
Why do you think there is this band
of clouds near the equator?
Did you figure it out?
• Warm, moist air in the topics _____
• Cold air holds ____ moisture than warm
air
• As moist warm air _____, it condenses
and forms ________!
The Wind Highways
• The Coriolis effect
causes air & water to be
deflected to the right
or____________ north
of the equator, and
_____________south
of the equator.
• This creates global
weather highways of
wind.
The Westerlies
• Because of our latitude, most
of our weather comes from
the ____
• Looking at the weather map,
what type of weather might
we expect? ________
• What type of weather might
we expect in a few days?
_________
short review
1.Transfer of heat in liquids or gases is
called _____.
2. _____ air is dense and tends to sink.
3. Band of clouds found around the
equator______
4. Cold air holds _____ moisture than
warm air
5. The Coriolis effect causes the air and
water to be deflected to the _____ of
the equator
Now What?
• Ok, so we know that the weather moves
around on these highways and that warm
air rises and cold air sinks.
• But why is it sunny one day, and rainy
the next?
Look at the weather map
• Notice that there are
___’s(blue) and L’s
(red) on the map
• blue lines w/ spikes
red lines w/ 1/2
circles
High Pressure Areas
• When cooler air sinks
& is warmed, the air
can hold ___
moisture.
• This usually means
_____ skies 
• Winds tend to move
clockwise around
high ______ ___
Low Pressure Areas
• When warm air rises & is
cooled, the air can not
hold as much ______.
• Often, these areas are
associated w/
_________ (hint: rain
snow sleet or hail) &
stormy weather
• Winds tend to move
_______ _____around
a low_______ _______.
If you see a big blue ___on the
weather map over your area, you can
expect______ weather
See a big red L in your area, there
will probably be______ weather
These highs and lows move more or
less along the jet stream and
brings changes in our weather
Fronts & Air Masses
• ____ _____is a large body of air whose
__________ & ________ are fairly
similar at a given altitude
• _____ are boundaries separating
different air masses
• There are _____ different air masses
that affect the United States
The Air Masses
• cP( continental polar) : ___, dry stable
• cT( continental tropical) : hot, ____,
stable air aloft, unstable at surface
• mP( maritime polar) : cool, ____,
unstable
• mT( maritime tropical) : ____, ____,
unstable
Map shows air mass source regions
and there paths
Ok, now we see the difference in
the air masses
* look at the different fronts & their impact on weather
• Can you see the four different types of fronts on the map?
Warm Fronts
* warm front is
warm air displacing
cool air diagram
*Shallow leading
edge warm air must
“overrun” cold air
*These are usually
_____ moving
Cold Fronts
• _____ air advances
into region of ____
air
• Intensity of
precipitation greater,
but short lived
• Clearing conditions
after front passes
• Usually approaches
from W or NW
Stationary Fronts
• Surface
positions of the
front do not
move
• Often a region
of clouds
Occluded Fronts
• Cold front
overtakes warm
front
• Often found close
to the low
pressure center
Ready for a little quiz?
You’ll need a sheet of paper
• Write your answers as we go
• Here we go!
1.
• Winds in a low
pressure system
move _____
around the low
L
2.
• Name type of
front found
close to point
3.
• Which fronts
would you expect
to have greater
precipitation,
but be short
lived as the
front passes?
4.
• Give the name of
the air
mass/front that
would have the
following
characteristics:
• cool, moist,
unstable
5.
That important weather word that refers to the
transfer of heat
(hint: rises and falls)
6.
In general, air near the equator tend to_____.
( rise or fall )
7.
What causes air & water to be
deflected to the right…
north of the equator?
8.
Which of the weather highways usually
controls our weather
9.
Warm air holds ( more or less )
moisture than cold air
10.
• If there is a big
H on the
weather map
where you live,
would you expect
fair or stormy
weather?
H
11.
Band of clouds
found around
the
equator______
12.
The Coriolis
effect causes
the air and
water to be
deflected to the
_____ of the
equator