Weather
What do we know about weather?
How do people measure and predict the weather?
Meteorologist
• A scientist who studies the weather
• What kind of tools do they use?
Thermometer
• Used to measure temperature
• measures the kinetic energy of air molecules
• Fahrenheit & Celsius thermometers
Anemometer
• Measures wind speed• a system of gears converts the number of
turns per minute into wind speed
Hygrometer
• Measures humidity
• the moisture in the air
Weather Vane
• Measures wind direction
• changes in wind usually lead to change in weather
Barometer
• Measures air pressure
• high pressure = clear cool skies
• low pressure = cloudy skies, moist air
• extreme low pressure = stormy weather
Cloud Conditions
• Observing clouds can tell a lot about the weather
Cumulus
• White & puffy
• fair weather
Cirrus
• High in the sky
• white
• thin & wispy
• fair weather
Stratus
• Low in the sky
• thick & gray
• usually bring rain
Cumulonimbus
• Tower high into the sky
• gray to black
• Thunderstorms, hail, tornadoes
• anvil shaped
How can rising air pressure lead to a prediction about weather?
Air Mass
• A large body of air that has the same temperature and humidity throughout
• take on the characteristics of the region over which they form
• 4 types in the the USA
Air Masses
– Categorized by moisture content and temperature– Moisture categories: m = maritime (wet) and c =
continental (dry)– Temperature categories: P (polar; cold), T
(Tropical; warm)
Continental Polar
• Cool dry weather
Continental Tropical
• Hot dry weather
Maritime polar
• Cool humid weather
Maritime Tropical
• Warm wet weather
Front
• Border where two air masses meet
• most weather changes occur along a front
• cold front = cold air mass moves under a warm air mass creating cumulonimbus clouds
• warm front = a warm air mass moves over a cold air mass forming stratus clouds
What kind of air mass causes hot humid weather?
Climate
• The regular weather pattern for a region
• precipitation & temperature determine climate
• seasonal patterns
• all patterns are driven by the sun
• proximity to the equator determines temperature patterns
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• What is the cause of the seasons?
• What are two major factors of climate?
• What kind of climate would you find near the equator?
• What kind of climate would you find at the poles?