Download Cloud Types and Precip

Ch. 18 - MOISTURE IN THE ATMOSPHERE
18.3 Types of Clouds
 Clouds are classified based on how they ____________ and their _________
 3 basic forms
o Cirrus: (= a curl of hair) ____________________________________
 Made from ______ ____________ at _______ _______________
 Seen in _______ ________, but can mean rain or snow is coming
o Cumulus: (= a pile) _______________________________________
 Formed by ______________ _____________ air currents
 Usually mean ___________ __________________
o Stratus: (= a layer) _______________________________________
 Form in sheets at __________ _____________
 Block out sunlight - associated with _____________
 3 levels of height  can have ___________ and ______________ variation
o High Clouds: ( ________________________ meters)
 Examples: ____________________________________________
o Middle Clouds: ( ___________________ meters)
 Examples: ____________________________________________
o Low Clouds: (______________________ meters)
 Examples: ____________________________________________
 Clouds of vertical development: (start at 2000 meters – mid/high)
 Example: ____________________________________________
Fog
 Fog: A cloud with its ___________ at or very near the ____________
 The only difference between clouds and fog is ________________________
____________________________________________________________
 Fogs caused by cooling
o Fog forms when ________ oceanic air moves over a _________ water
current, then wind blows it over land (Ex: ______________________ )
o OR fog forms over land as air temperature near the ground _________
overnight and reaches the dew point in the early _______________
 Fogs caused by evaporation
o Fog forms over water when water temperatures are still ___________,
but air temperatures have ______________________________
o ____________ and early ___________________
How Precipitation Forms
 Cloud droplets = < 20 micrometers. They must grow in volume by roughly
____________________________________ for precipitation to form.
 Cold Cloud Precipitation
o ___________________ _______________: Theory that relates the
formation of precipitation to two physical processes – ______________
and _____________________
o ___________________ ____________: the condition of water
droplets that remain in the liquid state at temperatures well below 0oC
 Water will freeze if it comes in contact with a ____________ object
(freezing ___________________ )
o ___________________ _____: the condition of air that is more highly
concentrated than normally possible  relative humidity is > 100%
 Warm Cloud Precipitation
o _______________________________ _______________: Theory
that says large cloud droplets collide and join together with smaller
droplets to form a raindrop. Opposite electrical charges may bind the
cloud droplets together.
Forms of Precipitation
 The type of precipitation that reaches Earth’s surface depends on the
_____________ _________ in the lowest few kilometers of the atmosphere.
 Types:
o ______________: < 0.5 mm in diameter. Fall slowly & close together
o ______________: >0.5 mm in diameter. Fall faster & farther apart
o ______________: six-sided ice crystals
 Air temp < -5oC & air is drier  __________________ snow
 Air temp > -5oC & air is wetter  ___________________ snow
o ______________: When a layer of freezing air overlies subfreezing air
near the ground, small particles of ice fall.
o ______________: When raindrops become supercooled (below 0oC)
as they fall, then turn to ice on impact. A.K.A. _____________ _____
o ______________: Ice pellets formed in cumulonimbus clouds. Form
layers of ice if carried upward by a strong updraft.
_____________________: Instrument used to measure the amount of rainfall