Clouds

1850

AltocumulusOften signal bad weather like thunderstorms because they precede cold fronts

1830

CirrocumulusFair, but cold weather. Can sometimes indicate hurricanes.

1820

CumulonimbusIndicate severe weather, thunderstorms, and tornadoes

NimbostratusProduces dull wet days

Cloud Formations

StratocumulusRarely produces precipitation but indicates approaching storms

Most pictures from:http://www.clouds-online.com/

CirrusFair to pleasant weather

CirrostratusSignify a change in the weather; thicken as warm front approaches as ice crystals increase production

AltostratusSignals the approach of weakened or upper level warm front

StratusProlonged cloudy weather, could drizzle

CumulusFair weather, but usually precursors to bigger storm clouds

Standing Lenticular Altocumulus CloudsMuch wind comes from these clouds; creates turbulence for planeshttp://www.srh.noaa.gov/abq/?n=features_acsl

Altocumulus CastellanusSign of instability in the air and indicate heavy rain and storms.http://en.wikipedia.org/wiki/Altocumulus_castellanus_cloud

Towering CumulusIndicates unstable air; indicate fair weather but can grow into a stormhttp://en.wikipedia.org/wiki/Cumulus_congestus_cloud