Chapter 2 Weather Factors Sections 4 and 5 Water in the Atmosphere Precipitation

Humidity Humidity is a measure of the amount of water vapor in the air. Relative humidity is the % of water vapor in the air compared to the maximum amount the air could hold.

Dew Point The temperature at which condensation begins.

Types of Clouds Meteorologists classify clouds into three main types: Cumulus = looks like cotton balls, low to the ground (2km to 18km), usually mean fair weather except for cumulonimbus clouds which bring thunderstorms Stratus = flat gray layers, middle altitudes, cover all or most of the sky making it cloudy out and can lead to drizzling, rain, or snow Cirrus = wispy feathery clouds, form at high altitudes with cold temperatures, made of ice crystals

What Is Precipitation? Precipitation - Any form of water that falls from clouds and reaches Earth’s surface.

Rain Most common type At least 0.5 mm in diameter

Sleet Ice particles smaller than 5 mm Rain which freezes through a layer of cold AIR

Freezing Rain Raindrops which freeze when they touch a cold surface.

Forms only inside cumulonimbus clouds during thunderstorms. Hail Pellets of ice larger than 5 mm. Forms only inside cumulonimbus clouds during thunderstorms.

Snow Water vapor in a cloud that is changed directly into ice crystals.

Review Questions Pg. 66 = #1-3 Pg. 70 = #1-4 Complete sentences and everyone turns in their own paper.