Weather Flashcards
Cirrus cloud description
Made of ice crystals
Thin and wispy
Usually indicate fair weather
High level
Cirrocumulus cloud description
Small rounded white puffs
Individually or in long rows
High level
Cirrostratus cloud description
Thin and sheet like - sun and moon clearly visible
Halo is common, indicating ice
Often precedes precipitation
High level
Altostratus cloud description
Grey or blue/grey
Often covers whole sky
Usually no shadows, sun/moon may shine through dimly
Mid level
Altocumulus cloud description
Mostly water drops, often supercoiled
Grey and puffy
Larger puffs and more dark/light contrast than cirrocumulus
Mid level
Stratus cloud description
Uniform and grey
Resembles fog that does not touch the ground
Usually no precipitation but light mist/drizzle possible
Low level
Stratocumulus cloud description
Low lumpy clouds
Low level
Nimbostratus cloud description
Dark grey, likely to bear rain
Low level
Cumulus cloud description
Puffy cotton
Flat base and round top
Vertical
Cumulonimbus cloud description
Thunderstorm cloud Very tall, often reaching tropopause Individual or grouped Large energy release from water vapour condensation Vertical
How is cloud cover measured? Explain/Describe
Measured in OKTAS
Observed and estimated
One OKTA is 1/8 cloud cover
Half the sky is 4 OKTAS, completely covered sky is 8 OKTAS
How are clouds formed?
Sun heats the ground (especially at a high angle to the ground)
As temperature rises evaporation and humidity increases
Warmer air can hold more water vapour
Air becomes less dense and begins to rise
As the air rises it cools
When it reaches the DEW POINT (point at which the air is saturated) the water vapour begins to condense onto particles in the air
This leads to the formation of clouds
