Cloud Formation
Mountains
Frontal Wedging
Convection
Convergence
Mountains
 Air moves upward when wind forces it
toward a sloping terrain such as a mountain
 As air rises, it expands and cools
 Dew point is reached and clouds form
 This level is called the condensation level
 Precipitation forms on windward side of
mountain (the side the wind is hitting)
 Rain shadow (little precipitation) forms on
leeward side of mountain.
Cloud Formation at Mountains
Frontal Wedging
 Fronts occur when two large air masses meet
 A warm front occurs when warm air replaces cold
air by sliding over it
 The warm air carries the moisture into the upper
altitudes and condenses to form clouds
 Often forms altocumulus and altostratus clouds
 A cold front occurs when cold air displaces warm
air and it pushes the warm air up and then clouds
form
 Often forms cumulonimbus clouds
Clouds forming at a weather front
Altocumulus Clouds
(mid-level clouds)
Convection
 Warm air rises because it is less dense
 It cools and expands as it rises
 Condensation occurs at the condensation
level and clouds form
 Often forms cumulus clouds or sometimes
cumulonimbus
 Convection cells form as warm air rises and
cool air sinks
Convection forms clouds as heat is
transferred in a fluid (air) as warm air
rises to the condensation level.
Cumulus Clouds
Convergence
 Occurs when surface winds converge (come
toward each other)
 Often occurs at low pressure troughs (the
big L on a weather map or at the boundaries
of two large air masses)
 Air rises as it comes together
 Clouds form as air reaches condensation
level
 Can cause lake effect snow
Convergence Clouds form when air
comes together or converges usually
at a low pressure area.
Cumulonimbus Clouds
Images
www.ccs.new.edu
www.eons.com
www.wildlandschool.net/proj/clouds
www.windows.ucar.edu
www.uwm.edu
www.epod.usra.edu