Transcript Clouds

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
Humidity 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 Clouds
Three Main Types
-Cirrus
-Cumulus
-Stratus
Cloud
Classification
-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