You can’t see me, but you feel me, you can’t touch
me, but I can touch you. I have been called the
“Breathe of the Gods”, or the killer and giver of life,
gentle and fierce, friendly and enemy, angry and
happy. The Native Americans called me Moriah,
and Snow Eater (Chinook). The Japanese call me
Kaze and in Russia I am called Veter. I can shatter
homes, or wake a child from a peaceful sleep or
bring relief in times of need. I can spread the most
dreaded diseases or bring a welcome freshness.
What am I?
The current state of the
atmosphere...what is happening right
Main points to remember as we
learn about weather:
The sun warms the earth’s surface and
therefore all the air above the surface
The earth is warmed most at the equator and
least at the poles---why?
The air above land is warmed more quickly
than air above water.
Warm air expands and rises, creating an area
of low pressure; cold air is dense and sinks,
creating an area of high pressure
Weather: The state of the atmosphere
at a specific time and place
the average motion of molecules
↑ TEMP= ↑movement of molecules= feels hot
↓ TEMP= ↓movement of molecules= feels cold
Warm air= expanding or rising air=
leaves behind L pressure
Cold Air=sinking air= leaves an area of
Wind MovementWind Movement
Uneven heating ofUneven heating of
the earth’s surfacethe earth’s surface
causes some areascauses some areas
to be warmer thanto be warmer than
As we know, warmAs we know, warm
always follows coldalways follows cold
to share it’s warmth-to share it’s warmth-
when this happenswhen this happens
in the atmosphere,in the atmosphere,
wind happens!wind happens!
What causes winds?
A wind is aA wind is a
movement of airmovement of air
from a area of highfrom a area of high
pressure to an areapressure to an area
of low pressureof low pressure
It is this difference inIt is this difference in
pressure that makespressure that makes
the air move=windthe air move=wind
direction and speed
The anemometer is
the tool we use to
Wind chill=↑ cooling
the wind causes
Local WindsLocal Winds
The land cools and heats faster than the ocean.
Water holds heat longer than land, and takes longer
to heat or cool.
SEA BREEZE During the day, the land
gets hotter faster than the
water. The heated air
rises, leaving behind an
area of low pressure.
Wind from the cooler sea
blows in to take the place
of that warmer air. These
happen during the day!
Land BreezesLand Breezes
At night the lands cools off faster than
the sea. Cool air sinks creating an area
of high pressure. Wind blows from the
land to the sea.
Global Circulation and WindGlobal Circulation and Wind
Solar energy is at itsSolar energy is at its
greatest around thegreatest around the
Horse Latitudes= 30°N and S of
equator =calm winds= worlds
Jet Streams= 10km above the
surface blow from the west to the east
Intense heat = Powerful
Warm, moist air rises and leaves behind anWarm, moist air rises and leaves behind an
area of low pressure. This is why most rainarea of low pressure. This is why most rain
forests are found along equatorial regions.forests are found along equatorial regions.
That air rises until it reaches the top of theThat air rises until it reaches the top of the
troposphere, where it can’t rise any further.troposphere, where it can’t rise any further.
It spreads out towards the polar regions HOTIt spreads out towards the polar regions HOT
follows COLD wanting to share its warmth.follows COLD wanting to share its warmth.
As it spreads it begins to cool and sink-As it spreads it begins to cool and sink-
usually 30usually 30°N and S of the equator- sinking°N and S of the equator- sinking
air produces an area of H pressure with dryair produces an area of H pressure with dry
conditions= desert regions on earthconditions= desert regions on earth
Some or the air moves back
towards the equator as it sinks...
Where do you think
they got their name?
Who were these winds
There was an area that sailorsThere was an area that sailors
avoided with their lives...avoided with their lives...
THE DOLDRUMS...THE DOLDRUMS...
is the area aroundis the area around
the equator wherethe equator where
the wind completelythe wind completely
dies out... whichdies out... which
meant death asmeant death as
soon as the freshsoon as the fresh
water ran out.water ran out.
Water in the Atmosphere:Water in the Atmosphere:
HumidityHumidity: measure of the amount of water vapor: measure of the amount of water vapor
stuck between molecules in the air. The air’s abilitystuck between molecules in the air. The air’s ability
to hold water depends on the air tempto hold water depends on the air temp
The hotter the air, the more water the air can holdThe hotter the air, the more water the air can hold
Cold air: molecules move slower so droplets of waterCold air: molecules move slower so droplets of water
can start to stick together=can start to stick together=condensationcondensation
Relative humidityRelative humidity: the amount of water vapor(%): the amount of water vapor(%)
compared to the amount the air can hold- tool used iscompared to the amount the air can hold- tool used is
100%=air is saturated100%=air is saturated
Clouds form when water vapor
condenses on dust, salt particles in the
The temperature in which condensation
begins is called the dew point
TYPES OF CLOUDS
Cirrus Clouds: wispy, feathery clouds
Form only at high levels,
therefore are made of ice
Types of Clouds
Cumulus Clouds: are puffy white cotton
ball looking clouds
These are thunderstorm clouds
Types of Clouds
Stratus Clouds: clouds that form in flat
layers- cover all or most of the sky and
are low level clouds
Air masses are masses of air that have
the same characteristics of the surface
over which it develops
descending (going down)=H pressure
ascending (going up)=L pressure
Fronts: the boundary between 2
Warm Front: warm air slides over
departing cold air- large bands of
Cold air pushes under a warm air mass.
Warm air rises quickly=narrow bands
of violent storms form
This is the symbol
for a cold front
2 air masses merge and force warm air
between them to rise quickly. Strong
winds and heavy precipitation will occur
This is the
symbol for an
Warm or cold front stops moving. Light
wind and precipitation may occur
across the front boundary
This is the
symbol for a
Reading a weather map
ISOBAR= connects areas of equal
pressure BAR comes from BARometric
Reading a weather map...
Isotherm: Connects areas of equal
temperature; therm means temperature