Cumulus - Formed by rising air currents
Classic puffy white clouds
Good weather
Stratus - Sheets or horizontal layers
Formed when air cools to dew point
Low, uniform, thin, wispy sheets
Fine drizzle
Cirrus - Thin, wispy clouds
Mares tails
Rain in 24 hours
Cirrocumulus - Rippled and thin
Mackerel skies
Ice crystals reflect light and create halo
May indicate rain in 24 hours
Alto cumulus - Puffy white/gray
Indicate rain in 8-10 hours
Altostratus - Gray/blue
Light rain/snow
Nimbostratus - Low, thick, dark grey
Steady rain/snow