Introduction to Clouds

Clouds

• Clouds consist of water droplets or ice crystals in Earth's atmosphere.
• Clouds vary in size, shape, and color.
• They can appear thin/wispy or bulky/lumpy.
• Clouds appear white because the tightly packed water droplets reflect sunlight.
• Approaching rain causes clouds to darken as water vapor clumps into raindrops, reducing light reflection.

Types of Clouds

• Cloud types correlate with weather patterns, assisting in weather forecasting.
• The three main groups are cirrus, stratus, and cumulus.

Cirrus Clouds

• Cirrus clouds are wispy, curly, or stringy and form high in the atmosphere, above 6,000 meters (20,000 feet).
• Typically composed of ice crystals, cirrus clouds usually indicate clear, fair weather.
• Their shape can show the direction of high-altitude winds.

Stratus Clouds

• Stratus clouds are horizontal, stratified, and layered, blanketing the entire sky.
• They form close to the Earth and signal a chilly, overcast day.
• Precipitation from stratus clouds usually comes as drizzle or light snow.

Cumulus Clouds

• Cumulus clouds are large and lumpy; the name comes from the Latin word for "heap" or "pile".
• They can stretch vertically up to 12,000 meters (39,000 feet) high, forming from strong updrafts of warm, moist air.
• Cumulus clouds can cause heavy precipitation.
• Weather varies based on height/size, with higher cloud bases indicating drier air and fairer weather; low clouds mean heavy rain or snow.

Cloud Height Variations

• Cloud classification accounts for their altitude and the precipitation they produce.
• The prefix "cirro-" indicates high-level clouds above 6,000 meters (20,000 feet).
• Cirrocumulus and cirrostratus are high-level clouds.

Cirrocumulus Clouds

• Cirrocumulus clouds are thin, patchy, sheet-like, and may look rippled or grainy.
• They predict fair, cold weather; in the tropics, they may indicate a hurricane.

Cirrostratus Clouds

• Cirrostratus clouds are thin and white, covering the sky like a veil.
• They are common in winter and can create a halo around the sun or moon.
• Rain or snow may arrive within 24 hours.

Alto- Clouds

• The prefix "alto-" denotes mid-level clouds with bases between 2,000 and 6,000 meters (6,500-20,000 feet).
• Altocumulus and altostratus clouds are mid-level clouds.
• Made mostly of liquid water droplets, with some ice crystals if it's cold enough.

Altocumulus Clouds

• Altocumulus clouds have patchy white or gray layers and seem made of fluffy ripples.
• Lower than cirrus clouds but still high, altocumulus clouds consist of liquid water and don’t often cause rain.
• They mean fair weather.

Altostratus Clouds

• Altostratus clouds are gray or blue-gray mid-level clouds with ice crystals and water droplets.
• These generally cover the entire sky and mean continuous rain or snow.

Nimbo- and -Nimbus Clouds

• The prefix "nimbo-" or suffix "-nimbus" denotes low-level rain/snow-producing clouds below 2,000 meters (6,500 feet).
• The word nimbus comes from the Latin word for "rain".
• Nimbostratus and cumulonimbus clouds are examples.

Nimbostratus Clouds

• Nimbostratus clouds cause continuous precipitation for many hours.
• These low-level, moisture-filled clouds are dark gray and often block sunlight.
• These indicate gloomy weather with continuous rain or snow.

Cumulonimbus Clouds

• Cumulonimbus clouds are also known as thunderheads.
• Thunderheads generate rain, thunder, and lightning.
• These grow on hot days as warm, wet air rises and appear like mountains or towers from afar.
• They indicate rain, hail, and tornadoes.