Clouds and Precipitation Weather Clouds and Precipitation

Have you ever just looked at clouds? Why do we have clouds? Why are there different shapes? What can they tell us about the weather?

Take Good Notes! There will be a quiz on this information

Understanding Clouds Clouds form as warm air is forced upward As the air is forced upward, it expands and cools

Understanding Clouds As the air cools, the relative humidity reaches 100% For more information on Relative Humidity click ☼

Water vapor begins to condense in tiny drops around nuclei Water vapor begins to condense in tiny drops around nuclei. Nuclei are small particles of dust, salt, and smoke in the atmosphere

Cloud Types There are many different cloud types

Cloud Types Can you think of the two main ways that clouds are classified? Shape, Height, and sometimes Rain Capacity

By Shape! There are three main cloud types that are based on shape Think you know any of them? Stratus Cumulus Cirrus

Stratus Clouds Stratus clouds form a smooth, even sheet They usually form at low altitudes

Stratus Clouds When air is cooled and condenses near the ground, a stratus cloud know as _______ forms Know the name?

FOG!

Cumulus Clouds These are masses of puffy, white clouds, often with flat bases They form when air currents rise

Cumulus Clouds They can be associated with both fair weather and…….when they get really tall ___!

Thunderstorms!

Cirrus Clouds Cirrus clouds are high, thin, white, feathery clouds containing ice crystals

Cirrus Clouds Cirrus clouds are usually associated with fair weather, but they may indicate approaching storms

By Height The prefix of cloud names can describe the height of cloud bases Cirro: High clouds above 6000m

By Height Alto: Middle elevation clouds between 2000 to 6000m Strato: Low level clouds below 2000m

Rain Clouds Nimbus clouds are dark clouds associated with precipitation

Rain Clouds When a nimbus cloud is also a towering cumulus cloud, it’s called a cumulonimbus cloud

Ready for a quick review? 1. Clouds can form when the relative humidity reaches ____% 2. In order for clouds to form, water vapor begins to condense around ____of dust, salt, and smoke

3. Clouds are classified by ____ and____ and sometimes rain capacity 4. Puffy, white clouds are called? 5. Mid elevation clouds between 2000 and 6000m

Let’s see how you did! 100 Nuclei Shape and height Cumulus Alto

Forms of Precipitation Precipitation (pre-sip-uh-tay-shun) is any form of water that falls to the Earth's surface.

Types of Precipitation The type of precipitation that falls to the ground depends upon the formation process and the temperatures of the environment between the cloud and the surface

Can you name the different types of precipitation? Rain Snow Hail Sleet Freezing Rain

Rain Rain develops when growing cloud droplets become too heavy to remain in the cloud and as a result, fall toward the surface as rain

Rain can also begin as ice crystals that collect each other to form large snowflakes As the falling snow passes through the freezing level into warmer air, the flakes melt

Rain from snow!

Snow Snow is formed when ice crystals form from water vapor that is in the clouds directly above your heads! This process is called sublimation

Hail Hail is formed when updrafts carry raindrops upwards into extremely cold areas of the atmosphere

Hail There the raindrops merge and freeze. When the frozen clumps get to heavy they fall to earth

Hail Hail can vary in size, from the size of a small stone to that of a baseball! So be careful

Sleet Sleet is frozen raindrops. Sleet begins as rain or snow and falls through a deep layer of cold air that contains temperatures below freezing that exist near the surface.

Sleet Rain that falls through this extremely cold layer has time to freeze into small pieces of ice

Freezing Rain Freezing rain is falling rain that cools below 0°C, but does not turn to ice in the air The water is “supercooled”

When the drops hit anything they instantly turn to ice!

Quiz Time

Ready? Nuclei for the formation of rain drops can be small particles of: A) salt, B) smoke, C) dust, D) all the above Which of these cloud types is not based on the clouds shape: A) stratus, B) nimbus, C) cumulus, D) cirrus

3. Mid elevation clouds between 2000 and 6000m: A) nimbus, B) alto, C) cirro, D) strato 4. This form of precipitation is supercooled: A) rain, B) snow, C) sleet, D) freezing rain

5. This form of precipitation stays frozen all the way to the ground: A) rain, B) snow, C) sleet, D) freezing rain Let’s see how you did!

The Answers! 1. D 2. B 3. B 4. D 5. B

The End!

Humidity and Relative Humidity Humidity is the amount of water vapor in the air Relative humidity is a measure of the amount of water vapor that the air is holding, compared to the amount it can hold at a specific temperature

Humidity and Relative Humidity When the air is holding as much moisture as it can, it’s said to be saturated

Can you explain this graph?

In the cool of the morning, the air can’t hold as much moisture In the cool of the morning, the air can’t hold as much moisture. We often have dew on a summer morning Once the air has warmed, the relative humidity drops since the air can hold more moisture

You’ve seen water on the outside of a cold drink? The cold air around the glass causes a lower temperature at which the air is saturated

You’ve seen water on the outside of a cold drink? The temperature at which air is saturated and condensation takes place is the dew point To return click here ☼