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?