This document discusses various cloud and precipitation formation processes: - Adiabatic cooling causes air to expand and cool as it rises, while wet adiabatic cooling occurs more slowly when latent heat is released. - Orographic lifting occurs when air flows over mountains, adding moisture on the windward sides. Convergence draws air together, forcing it upward. Local thermals also cause localized convective lifting. - Clouds are classified by height (high, middle, low clouds) and by type (cirrus, cumulus, stratus clouds and mixtures). Precipitation occurs through cold cloud processes like the Bergeron process or warm cloud collision-coalescence. - Rain,

1. Clouds and Precipitation Project
By: Matt Schaffer

2. Adiabatic temperatures changes and
expansion and cooling
• When air is cool it expands and when air is warm it
compresses
• The rate of cooling or heating of unsaturated air is
called dry adiabatic rate
• The wet adiabatic rate is the slower rate of cooling
when latent heat is added
http://hyperphysics.phy-
astr.gsu.edu/hbase/thermo/a
diab.html

3. Orographic lifting
• Orographic lifting is when air flow is blocked
• Many of the rainiest places on Earth are on the
windward side of mountain slopes
• When air reaches the leeward side of a mountain
the air has lost much of its moisture
http://05lovesgeog
raphy.blogspot.co
m/2011/04/types-
of-rainfall.html

4. Frontal Wedging
• In central America when masses of warm
air and cool air collide it produce a front
• Warmer air is less dense and raises
• Colder air is more dense and produces a
barrier over warmer air
http://www.erh.noaa.gov/rnk/N
ewsletter/Spring_2008/climate.
htm

5. Convergence
• Convergence occurs when air in the lower
atmosphere flows together
• Air flowing from more then one direction goes up
• The Florida Peninsula is an example of
convergence
http://apollo.lsc.vsc.edu/classes/met
130/notes/chapter6/lift_converge.ht
ml

6. Localized Convective Lifting
• Unequal heating of Earth causes rising parcels of
warmer air called thermals
• Localized convective lifting is the process that
produces rising thermals
• Pockets of air that are warmer then surrounding
air are less dense will move upward
https://www.meted.ucar.edu/sign_in.php?go_
back_to=http%253A%252F%252Fwww.meted.
ucar.edu%252Fnorlat%252Fsnow%252Flake_ef
fect%252Fprint_whole.htm

7. Stability
• The temperatures of that
atmosphere at various
heights determines the air
stability
• Stable air produces clouds
that are widespread, have
little vertical thickness
compared to their
horizontal dimension, and
precipitation is light to
moderate, if any
• Stable air resists vertical http://keithrogershome.com/Chap6Stab
movement and air stays in ilityInstability.html
its positions and unstable
air rises

8. Condensation
• The air must be saturated
for condensation to
occur(water vapor changes
to liquid)
• Condensation nuclei are
the surface for water vapor
condensation in the air
http://keep3.sjfc.edu/students/kes008
• Their must be a surface for 98/e-
condensation to occur port/condensation%20page%20for%2
0unit.html

9. Types of clouds
• The three basic forms
of clouds are
cirrus, cumulus, and
stratus
• All clouds show
properties of one of
the three basic cloud
forms or a mixture of
them
http://eo.ucar.edu/webweather/cloud3.html
• Clouds are classified
on their height and
form

10. High Clouds
• High clouds are made
up of
cirrus, cirrostratus, cirr
ocumulus clouds
• High clouds are thin
and white
http://ww2010.atmos.uiuc.edu/(Gh)
• High clouds are not /guides/mtr/cld/cldtyp/hgh/crs.rxml
considered
precipitation makers

11. Middle clouds
• Middle clouds are
2000 to 6000 meter
high
• Have the prefix alto
as part of their name
• Altocumulus clouds
are larger and denser
then cirrocumulus http://www.ifimages.com/public/im
age/139051/view.html
clouds

12. Low Clouds
• Low clouds are made
up of stratus,
stratocumulus, and
nimbostratus clouds
• Stratus clouds mostly
cover much of the sky
• Nimbostratus clouds http://www.cepolina.com/photo/str
come from a Latin atus_cumulus.htm
word that means rainy
cloud

13. Clouds of vertical Development
• Clouds that don’t fit into the three height
ranges are associated with unstable air
• When a upward motion is triggered it will
produce clouds with vertical form
http://www.free-
online-private-pilot-
ground-
school.com/Aviation
-Weather-
Principles.html

14. Fog (by cooling and by evaporation)
• Fog can be caused by
cooling or evaporation
• Fog is produced when
warm air moves over
cold air
• When cool air moves
over warm air it http://photoshoptutorials.ws/photoshop-
tutorials/photo-effects/fog.html
condenses and rising
making fog that looks
like steam

15. Cold Cloud Precipitation
• Formed by the
Bergeron process
• Supercooled water is
when water is in a
liquid state and below
0 degrees Celsius
• Supersaturated air has
100% saturated air for http://www.srh.noaa.gov/lzk/?n=mar
water and above 100% 2011.htm
saturated for ice

16. Warm Cloud Precipitation
• The collision-
coalescence process
forms rain drops in
warm clouds
• Larger droplets join
together with smaller https://www.meted.ucar.edu/sign_in.p
droplets as they move hp?go_back_to=http%253A%252F%252
Fwww.meted.ucar.edu%252Ftropical%2
through the cloud 52Ftextbook_2nd_edition%252Fprint_5
.htm

17. Rain and snow
• Rain is a drop of water
that falls from a cloud
and has a diameter of .5
mm
• Light snow occurs when
there is a small amount
of water vapor in the air
• Heavy snow occurs when
http://www.mapsofworld.com/world-
temperatures are warmer maps/precipitation-rain-and-snow-
than -5 degrees Celsius enlarge-map.html

18. Sleet, Glaze and Hail
• Small particles of
clear ice are called
sleet
• Freezing rain is
commonly known as
glaze
http://www.theweatherprediction.com/severe
• Cumulonimbus /gianthail/
clouds produce hail

19. The End