Ch. 16 Vocabulary

Front 1

Cirrus Cloud

Back 1

Form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds don’t usually produce precipitation, but they may be a sign that wet weather is coming

Front 2

Cumulus Cloud

Back 2

Are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus

Front 3

Dew Point

Back 3

The temperature at which water vapor condenses

Front 4

Fog

Back 4

Clouds that form on the ground

Front 5

Freezing Rain

Back 5

Falls as liquid water. It freezes on contact with cold surfaces near the ground. It may cover everything with a glaze of ice. If the ice is thick, its weight may break tree branches and pull down power lines

Front 6

Hail

Back 6

A type of frozen precipitation. Hail forms in thunderstorms when strong updrafts carry rain high into the troposphere. The rain freezes into balls of ice called hailstones. This may happen over and over again until the hailstones are as big as baseballs. Hail forms only in cumulonimbus clouds

Front 7

Heat Index

Back 7

A measure of what the temperature feels like because of the humidity

Front 8

Humidity

Back 8

The amount of water vapor in the air

Front 9

Relative Humidity

Back 9

The percent of water vapor in the air relative to the total amount the air can hold

Front 10

Sleet

Back 10

Forms when snow melts as it falls through a layer of warm air and then refreezes. It turns into small, clear ice pellets as it passes through a cold layer near the ground

Front 11

Stratus Cloud

Back 11

Occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means “rain.”

Front 12

Weather

Back 12

The conditions of the atmosphere at a given time and place.