Download Weather

Weather
Weather
• Weather refers to the state of the
atmosphere at a specific time and place.
• The one thing that you can talk to anybody
about
• If you don’t like the weather in Texas just
wait around it will change
Weather Components
• temperature, wind, clouds, humidity and
precipitation, air pressure and air masses
• List the component and tell what it is and
how it affects the weather on a daily basis
Temperature
• Temperature is a measure of the energy
of air molecules
• High temperature means fast movement,
low temperature means slower movement
Wind
• Wind is air moving in a specific direction
• As the Sun warms the air it expands and
becomes less dense and low pressure.
• Cooler air is more dense and sinks with
higher pressure
• Wind results because air moves from high
pressure to low pressure (cool to warm)
Wind Measurement
• Wind can be
measured with a
tool called an
anemometer
Clouds
• A visible body of water droplets or ice
particles suspended in the atmosphere
Cloud Classification
Precipitation
• Water that falls from the clouds
• Air temperature determines the form of
precipitation that falls
• 4 main types of Precipitation: Rain, Sleet,
Snow and Hail
Types of Precipitation
Rain
Sleet
Snow
Hail
Humidity
• Humidity is the amount of water vapor
present in the air
• Warmer air contains more water vapor
than cooler air
• Which has more water vapor?
Humidity cont’d
• Relative humidity is the measure of the
amount of water vapor present compared
to the amount needed for saturation
• Dew point is the temperature at which the
air is saturated and condensation forms
• The closer the temperature is to the dew
point, the more humidity there is
Humidity Measurement
• Humidity can
be measured
with a tool
called a
psychrometer
Pressure and Air Masses
• An air mass is a large body of air that has
properties similar to where it developed
• For example, one that forms over land will be
dry. One that forms in the tropics will be warm
• As these air masses move, weather changes
occur
• High pressure systems are usually fair and dry
• Low pressure systems are usually cloudy and
wet
Worldwide Air Mass Map
c=continental m=maritime
p=polar t=tropical e=equatorial
Isobars
Lines that connect areas of equal pressure
Sketch
this
picture
Fronts
• A front is a boundary between two air masses of
different density, moisture or temperature
• Cold fronts occur when cold air moves towards
warm air. They usually bring thunderstorms
Front’s Cont’d
• Warm fronts form when warmer air moves over
colder air. These usually form hours or days of
wet weather
Fronts Cont’d
• Stationary fronts occur when the boundary
between two fronts stops advancing. They may
remain in place for several days