This document summarizes different types of clouds and precipitation. It describes various cloud formation processes like adiabatic cooling, orographic lifting, and frontal wedging. It explains high, middle, and low clouds like cirrus, altostratus, and stratus clouds. Different precipitation processes are outlined, such as warm cloud precipitation through coalescence and cold cloud precipitation using the Bergeron process. Sleet, glaze, hail, rain, and snow are defined. The document is intended to provide an overview of clouds and precipitation types and formation mechanisms.

1. CLOUDS AND PRECIPITATION
PROJECT
BY: Paul Bean
Picture site:
http://science.nationalgeographic.com/
science/photos/clouds/

2. ADIABATIC TEMPERATURE CHANGES
AND EXPANSION AND COOLING
• Temperature changes that happen even though
heat isn’t added or taken away are called
adiabatic temperature changes
• They are the result of air being compressed or
allowing air to expand
• as you travel up from earths surface, atmospheric
pressure decreases because of fewer gas
molecules
• Picture site:
http://apollo.lsc.vsc.edu/classes/met130/notes/c
hapter6/adiab_cool.html

3. OROGRAPHIC LIFTING
• Happens when elevated terrain, such as
mountains, act as barriers to air flow
• As air goes up, adiabatic cooling causes clouds
and precipitation
• When air reaches leeward side, it warms
adiabatically, causing few clouds and rain shadow
• Picture site :
http://www.examiner.com/outdoorsman-in-salt-
lake-city/understanding-why-utah-has-the-
greatest-snow-on-earth-part-1-orographic-lifting

4. FRONTAL WEDGING
• Without it, the center of America would be a
desert
• In central North America, masses of warm air and
cold air collide, producing a front
• At a front, cool dense air acts as a barrier over
which the warm less dense air rises, this process
is called frontal wedging
• Picture site :
http://www.geo.hunter.cuny.edu/~tbw/wc.notes
/4.moisture.atm.stability/frontal_wedging.htm

5. CONVERGENCE
• It’s whenever air in the lower atmosphere flows
together
• Goes up because must go somewhere, can’t go
down
• Leads to clouds and adiabatic cooling
• Picture site :
http://10.85.0.4:8080/ibreports/ibp/bp.html?fn=
Students&fp=1&bu=www.islandnet.com/~see/w
eather/elements/whatgoesup3.htm&bc=Website
+contains+prohibited+Web-Based+E-
mail+content.&ip=173.49.166.199

6. LOCALIZED CONVECTIVE LIFTING
• The process that produces rising thermals
• Birds use the thermals to go high in the sky
and look down on their prey
• May produce mid-afternoon rain showers
• Picture site:
http://www.richhoffmanclass.com/chapter4.h
tml

7. STABILITY(DENSITY DIFFERENCES AND
STABILITY AND DAILY WEATHER)
• Stable air resists vertical movement
• If a volume of rising air was warmer and less dense
than he surrounding air, it would continue to rise until
it would reach an altitude where its temperature
equaled its surroundings, this is how hot air balloons
work
• Classified as unstable air
• Picture site:
http://ocw.usu.edu/Forest__Range__and_Wildlife_Scie
nces/Wildland_Fire_Management_and_Planning/Unit
_7__Atmospheric_Stability_and_Instability_1.html

8. CONDENSATION
• Happens when water vapor turns into a liquid
• Could be dew fog or clouds
• For any forms to happen, the air must become
saturated, normally when the air reaches its
dew point
• Picture site:
http://keep3.sjfc.edu/students/kes00898/e-
port/condensation%20page%20for%20unit.ht
ml

9. TYPES OF CLOUDS
• Classified on the basis of their form and height
• Cirrus(cirrus=a curl of
hair),Cumulus(cumulus=a pile), and
Stratus(stratum= a layer)
• High, middle, and low clouds
• Picture site:
http://www.enchantedlearning.com/subjects/
astronomy/planets/earth/clouds/

10. HIGH CLOUDS
• Three types, Cirrus, Cirrostratus, made of flat
layers and Cirrocumulus, fluffy masses.
• Don’t normally cause bad weather due to
height freezing water.
• Comprised of ice and minimal amounts of
water due to altitude.
• Picture site:
http://cluods.blogspot.com/p/introduction-
cloud-is-composed-of.html

11. MIDDLE CLOUDS
• Altocumulus and altostratus
• Cause infrequent drizzling(rain)and light snow
• Altocumulus clouds are larger and denser than
cirrocumulus
• Picture site:
http://cluods.blogspot.com/p/introduction-
cloud-is-composed-of.html

12. LOW CLOUDS
• Stratus, fog like, stratocumulus, scalloped
bottom and nimbostratus, causes most rain
• Nimbostratus’s Latin name means rainy cloud
to cover with a layer
• Nimbostratus clouds form under stable
conditions
• Picture site:
http://cluods.blogspot.com/p/introduction-
cloud-is-composed-of.html

13. CLOUDS OF VERTICAL DEVELOPMENT
• Some clouds don’t fit into any of the above
cloud formations
• These types of clouds are in the low height
area, yet can extend to the middle and high
height ranges
• They are all related to one another and are
associated with unstable air
• Picture snipped from Prentice Hall Book
Website

14. FOG(BY COOLING AND EVAPORATION)
• Can form when earth cools rapidly by
radiation
• Can be caused when cool air moves over a
warm body of water to produce saturation
• Common over lakes in fall and early winter
• Picture site:
http://lupusincolor.blogspot.com/2011/01/lup
us-fog.html

15. COLD CLOUD
PRECIPITATION(BERGERON PROCESS)
• Relies on super cooling and super saturation
• Whatever water the supercooled water
touches, it freezes that water
• Supersaturation allows more water to the ice
crystal to grow
• Picture site:
http://www.sleepingdogstudios.com/Network
/Earth%20Science/ES_18_Rev_files/frame.ht
m#slide0021.htm

16. WARM CLOUD
PRECIPITATION(COLLISION-
COALESCENCE PROCESS)
• Makes most precipitation
• Water absorbing particles remove water vapor
from the air at relative humidities less than
100%, allowing drops to be very large
• As these large drops move along, they join
with smaller and slower drops
• Picture site:
http://www.cbs6albany.com/sections/weathe
r/research/topics/topicfive/

17. RAIN AND SNOW
• Definition of rain is specifically drops of water
that fall from a cloud and have a diameter of
at least 0.5 mm
• Anything smaller is called a drizzle
• At very low temperatures, light fluffy snow
forms
• Picture site:
http://www.istockphoto.com/stock-photo-
2507583-ice-rain-and-snow.php

18. SLEET, GLAZE AND HAIL
• Sleet is the fall of clear to translucent ice
• Glaze is when ice drops are supercooled as they fall
through subfreezing air near the ground
• Hail is produced in cumulonimbus clouds, they start as
ice pellets that grow by collecting supercooled water
droplets as they fall through a cloud
• Picture site: http://www.lifeslittlemysteries.com/676-
how-big-was-the-biggest-hailstone-ever.html

19. THE
END!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
By: Paul Bean
Picture site:
http://www.flickr.com/photos/2703267
3@N02/2615193708/