4.1 Atmosphere Check-Point

form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. These clouds don’t usually produce precipitation but they may be a sign that wet weather is coming.

• Cirrus clouds
• Nimbostratus
• Altocumulus
• Cumulus clouds

occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo means “rain.”

• Stratus clouds
• Stratocumulus
• Cumulus clouds
• Nimbostratus

are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain they are called cumulonimbus.

• Cumulus clouds
• Cirrus clouds
• Stratocumulus
• Cumulonimbus

A type of cumulus cloud that is tall and gray, and associated with thunderstorms.

• Cumulonimbus
• Altostratus
• Altocumulus
• Stratus clouds

Low elevation layered clouds with tops and bottoms rounded

• Stratocumulus
• Cumulus clouds
• Stratocumulus
• Cumulonimbus

Clouds that are low-level, uniform layer, usually very dark, that bring strong precipitation

• Nimbostratus
• Cumulus clouds
• Nimbostratus
• Stratocumulus

Clouds at mid-level that form a light sheet that lets the sun or moon show as a bright spot.

• Altostratus
• Stratocumulus
• Cumulonimbus
• Altocumulus

Medium level cumulus cloud that is higher than regular cumulus clouds. Lead to precipitation.

• Altocumulus
• Altostratus
• Stratocumulus
• Cumulonimbus

forms at night. Skies are clear and the relative humidity is high. The ground cools as temperature goes down. Air near the ground cools below its dew point.

• Radiation fog
• Advection fog
• Steam fog
• Upslope fog

Warm moist air comes in from the Pacific Ocean. The air blows over the cold current. When the air cools below its dew point fog forms. Sea breezes bring the fog onshore. Famous in San Francisco California.

• Advection fog
• Steam fog
• Upslope fog
• Radiation fog