Download Weather

Meteorology, Factors effecting weather, and
forecasting weather
Meteorology
 Meteorology is the study of weather.
Meteorologist
 A meteorologist is a scientist who studies
weather.
Meteorologists study what is
happening and use their knowledge
to forecast the weather to come.
Different Tools
 Meteorologists use many different tools to
help them measure the weather.
 Thermometer – measure temperature
 Anemometer – measures wind speed
 Rain Gauge – measure amount of precipitation
 Barometer – measure air pressure
 Hygrometer – measures humidity
Thermometer
Anemometer
Rain Gauge
Barometer
Hygrometer
Meteorology
 There are many other things
scientists use to understand and
also predict the weather.
Air Pressure
Wind
Fronts
Clouds
Air Pressure
 The air around us has weight, and it
presses against everything it touches.
That pressure is called atmospheric
pressure, or air pressure.
Air Pressure
 Air pressure can change from place to place.
 The lower you are in the atmosphere, the
more air you have above you. All of this air
presses down creating more pressure or high
pressure.
 The higher you are, there is less air above
you. So, there is less weight pushing down
which is lower pressure.
Air Pressure
Air Pressure
 When we talk about air pressure
and weather, we usually talk about
two different kinds of pressure
systems.
Low Pressure System
High Pressure System
High Pressure
 A high pressure system, is a mass of cool, dry air. From
above the wind travels clockwise.
High Pressure
 High pressure usually brings fair weather,
light winds, and sunny skies.
 On a map, high pressure is represented by a
big blue H.
 Remember, High=Blue=Fair/Good (4
letters)
Low Pressure
 When warm air in the atmosphere expands, gets
lighter, and rises, it creates a low pressure area.
 Winds rotate counterclockwise.
Low Pressure
 It is a mass of warm, moist air that usually
brings stormy weather and strong winds.
 On a map, low pressure is represented by a
big, red L.
 Remember, Low=Red=Bad
Wind
 The air never stops moving – even if some days
it might seem like it does!
 What causes wind?
 Differences in temperature and the
amount of air in
two places
Wind
 Wind speed is measured using Miles Per
Hour (MPH)
 Wind is described in the direction from
which the wind blows. (north wind comes
from the north)
 We can show wind and wind speeds using symbols.
Wind
 The dot
points to the direction the wind is going.
 The tail points to where the wind is coming from.
 The barbs
show the speed, the more barbs, the
faster the wind!
Fronts
 If two or more areas have the same air pressure and
temperature, then meteorologists connect those areas
with a line (on a map).
 These lines show similar temperature, pressure, and
moisture – called fronts.
Warm Front
 A warm front is the front of a warm air mass.
 A warm front moves warm air above cooler air and
replaces it with warm air.
Warm Front
 A warm front is represented as a red line with half
circles pointing toward the direction it is moving.
 Warm fronts tend to bring steady, lighter
precipitation.
Cold Front
 A cold front is the front of a cold air mass.
 A cold front moves warm air above cooler air. The air is
then replaced with colder air.
Cold Front
 Cold fronts move quicker than warm fronts and cause
the temperature to fall. Cold fronts tend to bring
stormy weather.
 On a map, we a blue line to represent a cold front.
Clouds
 There are four basic cloud shapes.
 1. Cirrus
 2. Cumulus
 3. Cumulonimbus
 4. Stratus
Cirrus Clouds
 Cirrus clouds are the highest clouds. They look like
feathers across the sky. They are about 10,000 meters
above the Earth.
 They usually bring fair
weather.
Cumulus Clouds
 These clouds look like bright white wads of cotton
 They form at about 6,000 meters high
 Cumulus clouds are most often seen with fair weather.
Cumulonimbus Clouds
 These are the largest clouds. They are wide at the
bottom, narrow in the middle, and white and flat at
the top.
 They form at about 2,000 meters and can pile up really
high!
 These usually bring heavy rain, high winds, hail, and
tornadoes!
Cumulonimbus Clouds
Stratus Clouds
 These clouds form gray sheets that spread across the
sky.
 They from low, at about 1,500 meters and can sink all
the way to the ground!
 These clouds often bring heavy mist and snow or
drizzle.