What do clouds have to do with

weather?

What is it?

- A measure of the amount

of water vapor in the air.

Relative Humidity-The percentage of water vapor in the air

compared to the maximum amount the air could hold

Relative Humidit

y is measured using

a psychrometer

WET DRY

How it works

:-If the relative humidity is high, the

water on the wet bulb will not change

much.-The relative Humidity can be found by

comparing the temperatures on a chart like

this one.

How Clouds Form-Water vapor in the air becomes a liquid or ice crystals

Condensation

-As air cools, the amount of water vapor it can hold

decreases.-Some of that water vapor condenses to

form a liquid.

What is Dew Point?

-The temperature at which condensation begins

To Condensation

-For water vapor to condense, tiny particles

must be present so the water has

a surface on which to

condense.-Salt crystals,

dust from soil, & smoke.

Types of CloudsThree Main

Types-Cirrus

-Cumulus-Stratus

Cloud Classificatio

n-Clouds are classified by their shape and altitude-Each type of

cloud is associated

with a different type

of weather

Cirrus

-Wispy, feathery clouds

-Have feathery “hooked” ends

-Form only at high levels (above 6 km)-Made of ice crystals

Stratus-Means “spread out”

-Usually cover most of the sky

Cumulus

-Means “heap” or “mass”-Look like fluffy, rounded piles of cotton

-Usually indicate fair weather

“-nimbus”-Means “rain”-As stratus clouds thicken, they may produce rain and would be called “nimbostratus”

-Cumulus clouds that are tall with flat tops

often produce thunderstorms and

are called “Cumulonimbus”

Cirrocumulus

-Look like rows of cotton balls-Often indicate a storm is on the

way

“alto-”

-Means “high”-Form between 2 and 6 km.

-Main types are altostratus and altocumulus.

FoG

-Cloud that forms on or near the ground