Precipitation and Clouds

Cloud Formation Warm moist air rises Air expands and cools to the dew point Air becomes saturated Water droplets form on condensation nuclei Clouds consist of water droplets and ice crystals

Condensation Nuclei condensation nucleus, tiny suspended particles, either solid or liquid, upon which water vapor condensation begins in the atmosphere.liquidcondensation Think of it this way, the water droplet needs something to form around, this super tiny (often invisible to the naked eye) particle is that something.

Cloud Types What type of clouds have you heard of? Cumulus Stratus Cirrus Cumulonimbus

Cumulus They are the white and fluffy clouds These are convective clouds  Convection takes place inside them  Leads to bigger and fluffier clouds

Stratus Stratus clouds are uniform grayish clouds that often cover the entire sky. They resemble fog that does not reach the ground. Usually no precipitation falls from stratus clouds, but sometimes they may drizzle.

Cirrus Thin wispy clouds that form in the upper troposphere. Usually associated with “fair” or “pleasant” weather.

Cumulonimbus Anvil Shaped Cloud, associated with major storms – The taller the cloud the bigger the storm (generally) – They can reach 60,000 ft in height – It gets dark during a thunderstorm because the massive thickness of these clouds actually blocks out the majority of the suns rays, darkening the ground beneath it.

Cumulonimbus

Why the top flattens out Once the cloud reaches the tropopause (the boundary between the troposphere and the stratosphere) the cloud can no longer get taller, so it spreads out at the top instead.

Precipitation What kinds of precipitation is there? Definition - Cloud particles too heavy to remain suspended in the air fall to Earth. What does precipitation do for the environment? Rain, Snow, Sleet, Freezing Rain, Hail Cleans the Atmosphere

Rain Rain – cloud particles that fall from the sky, the atmosphere is warm enough that it falls as a liquid to the ground.

Snow Clouds that are exposed to sub-freezing temperatures develop ice crystals that fall to Earth as snow. In order to remain as snow, the temperature must stay below freezing from cloud level to ground level.

Sleet Clouds that are exposed to sub-freezing temperatures develop ice crystals that fall to Earth as snow. However, part of the air beneath the cloud is above freezing temperature, partially melting the snow. Then it is very cold at the surface, re-freezing the melted snow into little ice pellets.

Freezing Rain Cloud particles that fall as a liquid, they encounter a shallow layer of freezing cold air that causes the rain to freeze on contact with earth’s surface.

Why does it rain? Activity Why does it always seem to rain in the early evening? Fill in your worksheet as we move throughout the activity

Hail Ball of ice, can be big or small Updrafts lift up water drops high in the clouds It is so cold the droplets freeze – Droplets keep hitting the ice and freezing to it making a bigger ball of ice

Hail

Lightning Within a thundercloud way up in the sky, many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!

Lightning Fun Facts The spark can reach over 5 miles long Can reach over 50,000 o F, the surface of the sun is 9000 o F and contains 100 million electrical volts of energy Earth is struck by an average of 100,000 bolts per second The odds of becoming a lightning victim in the U.S. in any one year is 1 in 700,000. The odds of being struck in your lifetime is 1 in 3,000. Thunder is the sound of lightning cracking across the sky The empire state building is struck more than 100x per year

Lightning fun facts A lightning flash is no more than one inch wide. A stroke of lightning moves about 62,000 miles per second--one-third the speed of light. What we see as a flash of lightning may actually be three or four different strokes in exactly the same place, one right after another. That's why lightning seems to flicker. You are more likely to be struck by lightning twice in your lifetime than win the lottery for more than $350 million

A Bolt from the Blue One of the most dangerous types of cloud-to- ground lightning: – Comes out of the back side of the thunderstorm cloud – Travels a relatively large distance in clear air away from the storm cloud – Then angles down and strikes the ground.