High Cloud Name

Cirrus (Ci)

Source: JetStream School

-Thin and wispy
-Composed of ice crystals
-"Mares' Tails" sometimes used to describe them

-Usually a sign of current fair and pleasant weather
-High winds aloft create the wispy, streaming look
-Movement describes the wind pattern aloft

Cirrostratus (Cs)

Source: JetStream School

-Thinly cover the sky with ice crystals
-Sometimes halos can form from these clouds

-They usually form well ahead of a storm system high in the atmosphere
-They can be a sign of rain  or snow in the next 24 hours (especially if followed by middle level clouds)

Cirrocumulus (Cc)

Source: JetStream School

-Small, rounded puffs
-Sometimes develop in rows to have a rippling effect
-"Mackeral Sky" sometimes used to describe fish scale look 

-Usually develop in the winter
-May indicate cold, fair weather
-Occasionally in the tropics they could indicate an approaching tropical system
-Be cautious when forecasting the weather with these-- they form in many situations!

High Cloud Name

Altocumulus (Ac)

Source: JetStream School

-Puffy masses of white with gray edges
-Sometimes has a castle look called "castellanus" 

-Usually develop as a result of slow lifting
-Common in advance of a cold front
-Sign of rising air at cloud level
-Thunderstorms possible in the near future 

Altostratus (As)

Source: JetStream School

-Gray or blue-gray 
-Usually cover most of the sky
-Create a dimly visible or watery sun
-Composed of ice crystals and water droplets

-Usually develop ahead of storm systems
-A possible sign of stratiform (continuous) precipitation in the near future 
-Precipitation can start to fall to low cloud base to form a Nimbostratus cloud

Low Cloud Name

Nimbostratus (Ns)

Source: JetStream School

-Thick layer of low, dark gray clouds 
-Fog may develop below the cloud base

-Produces continuous precipitation that reaches the ground (rain or snow)
-Precipitation is usually light or moderate
-Fog can be associated with this cloud

Stratocumulus (Sc)

Source: JetStream School

-Low, lumpy layer of clouds
-Light to dark gray color
-Appear in rows, patches, or as rounded masses with breaks of clear sky

-Spreading remains of much larger cumulus cloud
-Indicative of small convective activity 
-Precipitation very rare in these clouds

Stratus (St)

Source: JetStream School

-Uniform in nature
-Poor defined edges 
-Sun is usually watery through these clouds
-Grayish color

-Sometimes caused by fog lifting
-Usually no precipitation, though sometimes light drizzle or mist is possible
-Flat top usually caused by temperature inversion 

Vertical Development Cloud Name

Cumulus (Cu)

Source: JetStream School

-Puffy and cotton shaped
-White or gray base  
-Cumulus Humilis: slight vertical growth
-Cumulus Congestus: ragged shape similar to cauliflower with much more vertical growth

-Develops when unstable air rises vertically 
-Cumulus Humilis is a sign of fair weather
-Cumulus Congestus is a sign of possible thunderstorm development (they could lead to Cumulonimbus) 

Cumulonimbus (Cb)

Source: JetStream School

-Cauliflower shaped cloud that extends from just above the surface to in some cases the stratosphere
-Sometimes has a distinct anvil shape

-Develops when unstable air continues to rise vertically
-Associated with thunderstorms
-Thunderstorms that can produce heavy rainfall, hail, wind and tornadoes if in the proper environment (adequate shear and instability)